Brutal Doom

Brutal Doom is a gameplay mod that was created in 2010 by Sergeant_Mark_IV. It is compatible with Doom, The Ultimate Doom, Doom II: Hell on Earth, Final Doom, TNT: Evilution, Plutonia and other custom WADs. Brutal Doom won the first ever Cacoward in 2011 for Best Gameplay Mod and a MOTY award for creativity by Mod DB in 2012.

Brutal Doom received public recognition by John Romero himself during the IGN gameplay video made for the 20th anniversary of Doom, stating that if they had released Brutal Doom instead of Doom back in 1993, they "would've destroyed the game industry" and that "Brutal Doom is hilarious" (said at 1:08:48).

Perhaps the most obvious and eye-catching feature of Brutal Doom is the adding of features like additional blood (blood gets splattered on walls and ceilings if enemies or the player get hit), the ability to blow off body parts with strong weapons like the shotgun, and the addition of special illuminating effects on projectiles and pick ups. It is compatible with the source ports ZDoom, GZDoom, Skulltag, and Zandronum.

While primarily a gore mod, it goes further and alters the gameplay by changing many other aspects, such as the sounds, graphics, and combat. One such change is the increased difficulty, making enemy behavior much faster, unpredictable and dangerous (many attacks do double the normal damage to the player) and altering their attacks. It makes the animations smoother and gives the player new abilities.

Primary changes (based on v21)
Fatality (on players): in v20, if the Imp kills the player via the jumping claw attack, the monster proceeds to tackle the marine in a horse-mounted stance and claw his/her face multiples times until the marine's head gets completely shredded. Fatality (on players): the Demon/Spectre rips and chews the marine's upper body multiple times, splashing blood everywhere; in v20, the Demon(s)/Spectre(s) will also devour the flesh off the dead marine multiple times in a horrible predatory hunger. Fatality (on monsters): the Demon/Spectre chews the Zombieman/Shotgunner/Chaingunner/Imp's body, swallowing their upper half and spitting out the lower half. Fatality (on players): the Cacodemon bites a player to death, a sideways animation will be shown depicting the monster eating the player's upper torso then dropping the player's mutilated lower half to the floor as the monster squares back up to the camera. Fatality (on monsters): same as the player's one but instantly without chewing. Fatality (on players): the Knight grabs the Marine, throws them roughly to the ground and crushes their head with a curbstomp. Fatality (on players): the Baron grabs the Marine and rips their body vertically, then pauses for a second and slowly keeps ripping the corpse in a sadistic bloodlust. Fatality (on monsters): the Baron grabs the zombieman/shotgunner, rips its head and throws the corpse towards the player (it also happens to the Imp but the Baron discards both halves without throwing them). Fatality (on players): the Revenant grabs and rips off the player's head, then nonchalantly drops both parts to the ground. Fatality (on monsters): the Revenant grabs the zombie/Imp through the leg, bashes them into the ground six times and throw them at the player, dealing very high damage - often killing the player with a direct hit, which range up to 300 damage.
 * When facing a monster, destructible object or a tree for that matter, the object's name & current health will be displayed at the top of the player's screen.
 * For example, when facing a Zombieman, the game will display "Pistol Zombie 50/50".
 * Former humans will make animalistic sentences such as "You! Die!" whenever they sense that the player is around.
 * Zombiemans now use pistols, SMGs or assault rifles, and will drop them when they die.
 * Shotgun's tube capacity has been changed to 10 before a reload is needed.
 * The new weapons added in this version are named The Railgun, The Unmaker and The Assault Shotgun.
 * The Railgun consumes ten plasma cells per shot, and can alt fire to zoom in the target.
 * The Unmaker shoots out tiny destructive flame balls, but consumes ammo rapidly. It's own source of ammo comes from human souls, which replenish by ten whenever the player kills Former Humans. The maximum ammo is 999.
 * The Assault Shotgun has 20 shells per drum magazine, but consumes shells at a fast rate like a rifle. It is powerful but it should only be reserved for powerful enemies such as the Cyberdemon. The player can also zoom in by pressing alt fire.
 * Dramatic increase of gibs and blood, creating a much gorier atmosphere.
 * Custom blood spray/splatter settings, ranging from 'Realistic' to 'Overdrawn at the Blood Bank'.
 * 3D bloodspots allow all textures to be covered with blood, including floors and ceilings.
 * More dynamic HUD - blood splashes on the screen if the player kills an enemy up close, and glass cracks or bullet holes may appear on the screen when the player gets injured.
 * When the player is critically injured (30% health or lower), the screen can become stained with tiny blood splatters and a dripping sound is played intermittently to imply the marine's blood is dripping to the ground (albeit this is just an audio/visual effect and does not incur further health loss).
 * New death animations for all enemies - body parts can be torn apart by shooting at various locations on the enemy's body with powerful weapons, cut in half with the chainsaw, melted with the plasma gun, burnt into smoky scorch by fire or electricity-based attacks, and blown to dozens of gibs by explosives.
 * Corpses can be further mutilated upon death - note that this feature has been removed as of v19 in the name of bugfixing, it is back as of Brutal Doom v21, where the player can extract monster weapons from the dead bodies of the Mancubus and the Revenant.
 * Many enemies have new attacks (more details below), and many enemy attacks do up to twice the normal damage.
 * The function to unload guns is now available from weapons (by pressing the unload key, by default U). Players can make use of this function to increase the amount of ammo for more powerful weapons. The only weapons that can be unloaded are Assault Rifle, both Shotguns and Plasma Gun.
 * All of the standard weapons have been revamped with new graphics and sound, and most have had their functionality changed, such as by making it necessary to reload or by adding secondary functions (see below).
 * Classic Mode was introduced in v20 - this mode removes the players 'modernized' abilities, such as kicking, offending, reloading, and grenade tossing, and brings back a newer, more powerful version of the classic weapon sets. Some weapons, such as the Chaingun, have new graphics. Many weapons still have the ability to headshot and destroy limbs when using mouse aim.
 * Overpowered Tanks and Helicopters has been added in game, however they cannot be found in most custom Megawads. The creator plans to readd them in the upcoming Brutal Doom Extermination Day Megawad.
 * Teleportation effects are now colored red/orange instead of green, and leave a red Baphomet-inspired inverted pentagram on the ground which fades out completely after a few seconds.
 * The berserk pack's capabilities are greatly expanded. With it, the player can perform fatality-style finishers on monsters which can replenish some health, depending on the current version. As of v19, Fatalities are performed at a faster speed and can overheal the marine, but now they heal 50% less of the health than in v18 or lower. Other abilities include grabbing and throwing Lost Souls and explosive barrels, and using mortally wounded monsters as meat shields (a mortally wounded monster will be twitching in agony, making constant pain noises, and bleeding). A meat shield will absorb a set amount of damage from projectiles, at the cost of the player being limited to using only the rifle while carrying the shield. While carrying the shield, it can also be thrown to deal significant damage. In v20, Fatalities are somewhat harder to perform (specially on Demons/Spectres and above) but more rewarding as they award the player with 10 health, as long the player's health is still under 200. A highly recommended strategy is to perform fatalities on Pain Elementals, so as to prevent them from exploding and causing the player damage. Note that for balance reasons, the player becomes invulnerable while the fatality animation plays.Shotgun Head.png
 * Players are able to obtain Shotgun Guy's head after performing a Fatality on him. The head only deals very low damage, and is only used as a gag to increase the excitement of the gameplay.
 * 2lb2nau.jpg in Doom II.]]Implementation of headshots for all monsters — except the Cyberdemon, Spider Mastermind, Cacodemon, Demon/Spectre, Lost Soul and Pain Elemental. Headshots deal as much as double damage (depending on the weapon), and can gib the monster's head for one of many special death animations (see the screenshot at the right). Autoaim does not assist in getting headshots - in fact, the "Weapon.NOAUTOAIM" flag has been added to all weapons to completely remove autoaim's function in order to balance Brutal Doom's gameplay.
 * New difficulty options ranging from Power Fantasy to Realism Mode, which showcase the increase of monster attacking speed and damage as the difficulty rises.
 * Marines.pngibility spheres are replaced with captured marines. Punching or pressing the use button near a captured marine (kicking, gunfire or chainsaw will only injure him) will free him and he will follow and aid the player against the demons - note that as of v20, ONLY pressing "Use" will rescue the marine. Captured marines spawn with random weapons (ranging from assault rifles to plasma guns, the most powerful ones being less probable to spawn with the marine) and starting from v19, occasionally throw grenades. If a freed marine is killed in battle, his weapon will be dropped for the player. An allied marine can punch enemies at close range and even perform fatalities (like the player, becoming invulnerable in the process) to replenish his own health. However, any nearby demons will attempt to kill any restrained marines as soon as they are in the player's sight. Players are advised to quickly rescue any marines they see tied up while fighting the demons, as they can be a great help in fighting Hell's spawns. They are very tough and is capable of becoming a meatshield, thus they are able to take a lot of hits, and use the same pain sounds as the player. As of v19, marines has become much more intelligent and will follow the player anywhere, via running/teleporting - however, there is an optional mutator that restores the Partial Invisibility spheres. Starting in v20, pressing "Use" near the marine will alternate between "following" and "holding position" modes, and friendly fire against marines is disabled in order to prevent accidental friendly damage and they are also immune to damage from Barrels and Damaging Floors. However, Marines will be damaged at an alarming rate if they are left alone surrounded by monsters and will be killed within no time. Marines will also randomly follow the player to the next level. Captured Marines can also be turned to "Evil-Marines" by nearby Archviles, therefore turning the Marines into a permanent enemy.
 * BDoom Partial.png As of Brutal Doom v20, after killing a Spectre, they will sometimes drop a Invisibility sphere, albeit at a low rate.
 * The Light amplification visor now has also thermosensitive lenses which display the entire ambiance in a full green hue and differentiate all heat sources - such as torches, lamps, force fields and even living organisms, whether players or monsters - with a bright tinge of fluorescent green.
 * If the player kills certain monsters by gibbing (or shreds their corpses with the chainsaw), they can sometimes take their weapons. This includes the Revenant's twin rocket launchers and the Mancubus's flame cannon, both mapped to key 8 (key 9 for the Mancubus cannon in v18 onwards).
 * Enhanced lighting and shadow effects for decorations and projectiles similar to those found in the Doomsday engine.
 * Enemy bullets now act as projectiles, albeit very fast ones, allowing the player to dodge them given sufficient time and distance. They are generally more accurate than their hitscan-based vanilla counterparts, especially at a distance.
 * A kick attack has been added to shove enemies away from the player, similar to the one in Duke Nukem 3D. It is bound to Q by default. Like the fists, this attack is powered up by berserk as well. If performed while jumping, it becomes a flying kick with the marine's foot turned 45 degrees, dealing even more damage. A "weaker" version of the flying kick can be performed on the ground as part of a combo (see below).
 * (For the sake of explanation, please consider the "MONSTERS: X/Y" information field in the automap, where X is the count of defeated monsters and Y is the total count of monsters in the level) A minor bug involves monsters (mostly zombies and Imps) who get killed by being kicked off heights: if the aforementioned monster gets kicked off the height (but being still alive), falls and dies by "splatting" against the ground, the count of X is not increased by one (which makes the X/Y count unequal and thus ruins 100% kills), but this counting flaw does not occur if the kick itself is the killing blow (in this case the X count is increased normally) whether it launches the monster downwards or not.
 * The fists are faster and can make quick jabs. Unlike in the vanilla Doom, they are now a silent attack and will not alert enemies. The alt-fire throws a slower but more powerful right-handed straight punch. Punching a Zombieman, Shotgun Guy, Heavy Weapon Dude or Imp from behind before the enemy has noticed will snap their neck, killing it instantly without alerting other enemies (this is especially easy to do at the beginning of MAP01 and MAP02 of Doom II and does not require a berserk pack).
 * A basic martial arts-style combo system was implemented in v19, allowing the player to quickly chain punches and kicks together with proper timing in attack key press. The "root" combo is comprised in this 3-hit punch sequence: left-hand jab, right-hand straight punch, left-hand horizontal hook punch, every one with increased power. Note that punches do not necessarily have to hit anything in order to activate one another. The third punch is capable of: knocking demons across the room, knocking off the heads of Imps and zombies and hitting Barons of Hell and Hell Knights in the crotch, stunning them and making them scream in pain. Also worth note, the third punch, even without the berserk pack power, will never perform fatalities or neck snaps, and will always gib/smash enemies to pieces without leaving their legs standing and/or attached. If the kick attack key is quickly pressed with correct timing right after any punch, a weaker version of the flying kick will be performed while on the ground (with either foot, depending of the punch used prior). The in-combo kick is stronger than the "regular" kick but weaker than the flying kick. The only downside of the in-combo kick is that the kick's "recoil" pushes the player's aim upwards at every use, much like did the minigun's continuous fire in v18. As of v20b, however, punch sequences are no longer possible (though the player can still chain punches into kicks individually) because the primary fire key throws weaker but faster jabs while the secondary fire key throws stronger but slower straights/uppercuts (both punches employ both arms randomly).
 * The chainsaw gets covered in blood splatters when sawing an enemy. It previously used the Doom 3 chainsaw sound but as of v19 and above it uses a improved Doom/Doom II sound. In v20b, the alternate fire key swings the chainsaw in clumsy but deadly horizontal patterns.
 * The pistol was re-introduced in v21, where it is the weakest long ranged weapon. It can be dual wielded and has a higher firing rate compared to its classic counterpart. This two benefits makes it somewhat not useless, although it can only be used in situations where low health monsters are present in low quantities.
 * The assault rifle is now introduced in Brutal Doom, which remains useful even late in the game. The rifle has a decent fire rate (close to the original chaingun) and is the most accurate weapon in the mod. The alt-fire mode allows the player to aim down the sights to snipe at enemies. It has a magazine size of 30 (31 in v20).
 * Starting in v20, the rifle is fully redesigned and has a much more accurate and faster fire rate. After obtaining another rifle (signaling by the status bar face's smile when the player acquires a new weapon), the player can press the corresponding weapon key to wield 2 rifles consecutively, John Woo style. Both rifles can be fired simultaneously via primary and secondary fire keys (doubling ammo clip size to 62), but the alt-fire "sniper mode" cannot be accessed while in "dual fire" mode. The "sniper mode" is now more powerful but highly unreliable due to its extremely erratic recoiling. Note that dual-rifle mode is now comparable to a minigun and is good at dispatching specific monsters such as Demons and even a Baron of Hell at high speed and shouldn't be used to kill weak enemies such as zombies, Imps and Lost Souls.
 * An interesting fact about the rifle's continuous fire is that, the primary fire mode's recoil ENDS at the first shot (meaning the second shot onwards is exactly straight) but the secondary fire mode's recoil STARTS at the fourth shot (meaning only the first three shots will be perfectly accurate, which may lead to players resorting to the old "key tapping" trick in order to properly shoot during sights aim). This "technical" information may come in handy on how to deal with the new assault rifle's attack behaviour. The erratic random recoil of the sniper mode was fixed in v20b.
 * The shotgun now fires ten pellets per shot instead of seven, to balance it with the Super Shotgun. Like the assault rifle, the sights can be used to reduce spread. It holds 8 shells, which are reloaded individually (and can also be shot "emergencially" in-between the reloading process by holding down the fire key). Aesthetically, it is now more tactical in style, giving it a black synthetic pump and stock instead of wooden ones, and also has a vented heatshield on the barrel.
 * The super shotgun receives an additional damage boost at point-blank range. It now has the option of firing only one barrel at a time, thus shooting only 10 pellets. It also has the ability to kill a Hell Knight or Cacodemon with both barrels fired at close range at head-level (doing this point-blank results in the body hitbox getting in the way of the shot).
 * The chaingun is now correctly referred to as a minigun (as well as resembling the more traditional design of said guns), and fires 50% faster but also requires a spin-up and cool-off before and after firing. The alt-fire mode makes the barrels continuously spin, further increasing the firing rate but also drastically decreasing the accuracy and alerting monsters (due to spin noise).
 * In v20, the minigun once again recoils during primary fire, this time "mixing" the vertical v18 and horizontal v19 recoils, drastically reducing the gun's shot accuracy (unless the player keeps "correcting" his aim manually).
 * Cacodemons are able to avoid both the Rocket Launcher and the Minigun when they are fired, making them much more difficult enemies.
 * The rocket launcher has a much smaller splash damage area, but it causes 50% more damage on a direct hit. It holds 6 rockets per clip.
 * The plasma gun deals roughly double damage and can cause minor splash damage to enemies (and players, if the bolt hits a nearby wall), but fires at a slower rate. As of v19, the alternate fire mode fires a continuous flamethrower-style spread of blue flames, inflicting great deal of damage over time but depleting the plasma cell extremely quickly. It has a clip size of 50. As of v20, the flamethrower attack is moved on to the Mancubus Flame Cannon, the old plasma gun sprites were completely restored and the original "shotgun spread" attack returns as the gun's secondary fire mode, but now it must powerup for a few seconds (it costs 10 ammo and can be delayed indefinitely by holding down the secondary fire key) before discharging the plasma shots, after which it produces an upwards recoil on the player's aim, dealing 500+ damage, and can be used to instantly kill a Hell Knight. The secondary attack can be cancelled in order to preserve ammo by pressing the reload key at anytime during the charging/delaying process.
 * BDoomDualFire.png v20, the player can find another plasma gun and wield 2 simultaneously and fire both at the same time by pressing both primary and secondary fire keys (at the cost of having no secondary fire mode), just like the assault rifle. However, dual wielding plasma rifles has a very powerful attack power and can be used to kill powerful enemies quickly. The damage output is comparable to a BFG, but eats up Cells at a more faster rate.
 * The BFG9000 uses the Doom 3 BFG sound effects and the primary energy ball deals double damage. Instead of the original BFG's hitscan tracer attack, it simply deals damage in a very large radius, like an even more powerful rocket launcher, except the rebound splash damage.
 * The Mancubus flame cannon, mapped to key 9, produces a short-ranged but powerful stream of fire. The attack has a very erratic recoil, similarly to the minigun, and costs 4 ammo per use. The secondary fire mode shoots fireballs at the cost of 15 ammo. These fireballs (as of v20) have no gravity akin to the Mancubus itself and so player does not need to work out the trajectory of the shot. Also, backpacks refill 100 ammo of the flame cannon. The flame cannon can only be removed via berserk-powered kicks, rockets, barrels, grenades which deal the killing hit. Normal Mancubus drops 100 ammo upon specific kills.Grenade.png
 * Grenades are introduced in v20. It is a very powerful item, it has almost twice the blast radius of the barrel, and can deal damage up to 500+ Max. Zombiemen and Shotgunners will sometimes drop 1 grenade upon dying, and the player can carry up to 10 grenades (20 after acquiring a backpack) at any time. Each backpack awards 5 grenades for the player. The most effective use of the grenade is perhaps by throwing them down a cliff that is filled with monsters, throwing them in a room you know that is full of monsters, and the player can switch to the grenade by pressing "0" - in such usage, the primary fire key throws the grenade a longer distance while the secondary fire key throws a shorter distance - or by pressing a specific "shortcut" key bound to it (normally "G" by default) - in which the player performs only the longer distance throw. The grenade has also proved to be very useful in dispatching huge enemies gathered for an ambush in a single tight area. Players should use it whenever a chance comes by.
 * Most weapons push the player back a tiny bit upon firing, especially the Super Shotgun and the BFG9000.KickBonus.png
 * Some monsters in the game could enter a "critical mode" after being shot to near death. In this mode, Players could go up and kick the monster, or ending it with a blast from various weapons, thus ending in a bloody death and earning the player a 5 health bonus or 5 armor bonus. As Critical Mode will eventually end up with the monster dying on its own after some time, it is advised for players to take the bonus as soon as possible when the chance occurs.
 * In Versions 21 and beyond, the maximum limit the player can reach through collecting health and armor bonuses is 300. However, it is possible to break that limit by abusing cruelty bonuses from monsters by using weapons such as the Shotgun and Minigun.
 * Offend.png The player is able to flip monsters off while shouting rude comments like "go fuck yourself" (voiced by Tony Danza, originally Danny Glover) by a bindable command known as "offend". This command will alert nearby monsters as if the player had just fired a weapon as well as offend them (hence the name) causing some enemies to attack more frequently. There are other bindable commands, such as "wave". Pressing the wave button during a fatality (see below) will allow the player to see his own wave animation in third-person, however you can take damage while waving. As of v20, the player can offend with two middle fingers when not equipping any weapons with the Offend command.
 * Only the Cyberdemon, Mancubus, Pinky, Spectre and Zombieman are susceptible to "Offend", increasing their attacking rate - in the latter case, the Zombieman will keep shooting forever in salvos of 3 shots, without even stopping to reload its rifle and even if the player has moved out of its sight. The Pinkies and Spectres will speed up when offended, making them harder to aim at.
 * There are several voice acted taunts and one-liners voiced by Chinese Tony Danza, that can be spoken with keys J and K by default. Many of these quotes are taken straight from the infamous Doom comic. Note that as of v19, these have been cut due to overuse in multiplayer games and will be in an optional mutator.
 * Both the Grenade Launcher and the Rail gun from the Skulltag source port have been given new sprites and attributes. The Grenade Launcher is a standard issue M79; it has a much larger blast radius than the Rocket Launcher, but fires much slower as well as dealing less damage. The Rail gun fires at a slower rate than the vanilla Skulltag Rail gun but uses half as much ammunition, has a scope for zooming in, and reloads after 5 shots instead of 4. However, both weapons seem to have been removed in v20. The weapons were re-added to the mod in v20b.
 * New sprites for the rockets and box of rockets, backpack, armor bonus, armor and megaarmor.
 * Most enemies that have been alerted can eventually lose track of you. If this happens, they will start to "patrol"- the enemy will slowly move around, periodically stopping and looking back and forth, before moving again.
 * Zombiemen will fire in salvos of 3 shots, with moderate accuracy compared to their vanilla design. They now can survive a few more bullets, and generally are significantly more competent enemies. After 20 shots, they must reload, with a new animation (which is very incomplete, as the zombie turns towards the camera when reloading its rifle before resuming its previous direction). They seem much more intelligent than their vanilla counterparts.
 * Shotgun Guys (Former Sergeants) now fire 7 (8 in v20) pellets per shot instead of only 3. Like the Zombieman, they also must reload their weapons (by inserting 5 or 6 new shells) at times - just like the Zombieman, the Shotgun Guy's reloading animation is also incomplete, as it has only the camera-facing frames of the reload process. Like the Zombieman, they can back up when at close range, have more health, and are more intelligent overall.
 * As of v19, Zombiemen and Shotgun Guys can enter into a last stand and pull out a pistol when they have one of their limbs cut off. They will then die by themselves after making their last shots or be killed by being attacked again.
 * (For the sake of explanation, please consider the "MONSTERS: X/Y" information field in the automap, where X is the count of defeated monsters and Y is the total count of monsters in the level) This causes a minor bug in which the former human's "last reaction" will increase by one the Y count and if the agonizing zombie dies by itself instead of being killed by the player (or another monster), it won't increase the X count, thus making both counts unequal, which prejudices players who gun for 100% kills.
 * In v20, both Zombieman and Shotgun Guy can also backtrack a few steps before firing if the player (or another monster if they are attacking each other) gets too close to them, perhaps for more accurate shots, adding to the militaristic realism of their combat AI.
 * Chaingunners now have completely redesigned sprites and carry a heavy handle-held minigun very akin to the player's. They take exactly half a second to aim before shooting (evidenced by its preceding revving sound), making them quite in par with their Doom 3 firearm-wielding counterpart.
 * Wolfenstein SS officers changed radically into soldiers in accurate SS uniforms with a demonic appearance and fanatical military voices. They possess more complex behavior, frequently dashing diagonally left and right, making them hard to hit. Their powerful MP40 submachineguns, mapped to key 8 (key 0 in v18, key 2 in v20b), can be picked up and used by the player. The MP40 has a higher rate of fire than the assault rifle and a 32-round magazine. This was removed as of v19 but will be added in the optional mutator in v20b.
 * The Imp now has a jumping pounce attack like the new imp from Doom 3 that it will use at close range, and can sometimes shoot two fireballs in quick succession. Its projectiles are now much more detailed, with several sound and visual effects. The player will have bloody slashes marking his screen in the direction an Imp connected with a melee attack.BDoomClawDeath.png
 * Melee-oriented monsters, such as Hell Knight and the Demon, will perform fatalities on the player and even other monsters if they kill them with a melee attack.
 * Demons and Spectres are faster, both in movement, evasion and attack speed. The latter ones are completely invisible, save for their eyes, making them much harder to detect — however, they briefly flash into a partial translucent state upon attacking and taking damage. They become fully visible upon death, with a red gaseous substance marking the kill (the red gas is removed in v20). Being melee-only monsters, Demons and Spectres will always perform any available Fatalities on a successful kill (Spectres only will do this starting in v20, becoming partially visible while doing so).
 * In v20, sometimes the Demon/Spectre will have one of its arms shot off (the Spectre loses its invisibility ability and becomes a full Demon) and scream in pain, and one of these two random things will happen: the monster will either collapse by itself (either instantly or after agonizing impotently for a few moments) or enter a "last rage" mode in which it will run, dodge and attack much faster and more ferociously but eventually dies after a few seconds due to profuse bleeding (or can be killed by attacking it again). Both instances of the first situation allow the player to gain a health boost by exploding the Demon/Spectre's head with chainsaw or gunfire if done rapidly enough.
 * (For the sake of explanation, please consider the "MONSTERS: X/Y" information field in the automap, where X is the count of defeated monsters and Y is the total count of monsters in the level) The Demon/Spectre's "last rage" mode, similarly to the Zombieman/Shotgunner's "last reaction" mode as seen above, causes a minor bug in which the Y count gets increased by one but if the monster collapses by itself (instead of being felled by a player or another monster) the X count won't be increased, which ruins any chances of 100% kill count.
 * The Cacodemon will frequently shoot two consecutive projectiles and can shunt itself out of the way of incoming attacks. It also floats a bit faster than its classic Doom counterpart. Aesthetically, their melee attack now has actual sound effects, unlike the classic Doom Cacodemon's silent gaping maw. As of v19, can be killed with a single shot from the super shotgun at point-blank range.
 * The Hell Knight now can sometimes shoot three consecutive projectiles, in a similar fashion to the Imp and Cacodemon. As of v19, it can be sometimes killed instantly with a point-blank headshot from the super shotgun.
 * The Baron of Hell has gained two new projectile attacks: first, it can launch three (five in v20) of its fireballs in a wide spread, which takes longer for the Baron to wind up. The second attack is after a former human gets into a infight with the baron and the baron wins with a melee, the Baron will either rip the head off (Zombieman) or in half (Shotgunner) then throw the corpse at the player, dealing nearly 300 damage. In v20 the Baron has a third new attack, where the monster can grab and throw exploding barrels, similarly to a Berserk-powered player.
 * Starting in v20, both the Knight and Baron now use the PlayStation's Final Doom version of the "generic demon pain scream" (which seems to be more "fitting" to their size and physical structure) when injured, rather than the original PC's version shared by other monsters.
 * Starting in v21, Barons cannot be killed in a single headshot through the SSG anymore.
 * Chaingunners, Hell Knights and Barons of Hell can be kicked (the latter two ones can be 3-hit combo'd too) in the crotch, stunning them for a few seconds (applies only in v18 and v19, removed in v20).
 * Arachnotrons are much larger, around the size of a Baron of Hell, and also move faster. Their plasma shots now are the same firing sound and blue projectiles fired by the player's own plasma gun.
 * Lost souls now have half of their original health and deal less damage, but fly around and attack much faster, which can potentially cause unlucky or slow players to miss attacks constantly — making them one of the more frustrating enemies in the game. Their flames have been removed from the sprite and are now generated by particle emitters. Upon death, Lost Souls explode in a fire puff and leave small scorched bone chunks on the ground. Also, they no longer bleed when attacked, emitting instead metal sparks and even a metallic "rashing" sound when attacked via chainsaw. As of v19, when killed they emit the same death screams from their Doom 3 new version.
 * Pain Elementals explode upon death (unless killed via fatality), causing heavy damage to nearby environmental objects, monsters and the player as well.
 * Revenants always fire two guided missiles at a time (matching their animation of both shoulder cannons lighting up when firing), and non-guided missiles are fired in volleys of four. Guided missiles are slower, have a much more limited fly pattern (they tend to travel downwards to the ground unless they can reach their target or hit any obstacle) and are now indicated by a reddish glowing color. Non-guided missiles are fired more rapidly, fly faster and straighter, and glow with a yellowish lens flare effect. As of v19, Revenants can be cut in half (either by the chainsaw or blasted in two parts by the super shotgun or any explosive means such as the rocket launcher), after which their upper half will remain alive, dragging itself across the ground and attacking (though only by firing single missiles and no longer by punching).
 * Mancubus fireballs have a blast radius that deals slight fire damage. They leave damaging flames for several seconds after hitting a surface. For v20, the creature also has a short-to-medium range flamethrower attack, and will use it once its target moves closer to itself, the same one used as the secondary fire mode by the player's version of the flame cannon. Also in v20, Mancubi who are hit by rockets or point-blank super shotgun attacks will be knocked back and stunned defenseless for a moment, rendering them unable to retaliate rapidly and buying time for players to attack them relentlessly.
 * An Arch-Vile's attack takes longer time to charge, however they can resurrect enemies without having to stop and face the monster's corpse. Their appearance has also changed, as they now have a new "soft death" animation and sport large stereotypical ram-like demon horns. They can also convert Tied Marines into Evil Marines, which then will attack the player with their equipped weapon.
 * The Cyberdemon has a new melee attack: a devastating stomp which against the player always means instant death (a homage to the Doom 3 version). In addition, it shoots its fire-engulfed rockets faster and for longer (four per volley instead of three), in a wider angle, giving it a limited ability to lead its shots against circle strafing players. As of v18, using the "Offend" command in front of the Cyberdemon will enrage him, drastically increasing his aggression, firing speed, and the amount of rockets fired per attack the cyberdemon can be offended 3 times unlike other monsters and roars when further enraged. Visually, its death animation has been enhanced with a massive 3D explosion that, in v16 and below, will deal damage. As an aesthetic correction, the rockets are now fired from the Cyberdemon's rocket launcher arm instead of the middle of his legs.
 * The Spiderdemon's gatling gun now fires high caliber explosive rounds, essentially a mini-rocket launching chaingun. Its reaction speed is now much faster, nearly instantaneous, giving the player little time to get out of its way. However, its projectiles travel slower than normal bullets, so with enough open space they can semi-reliably be avoided, not taking spread into account. Perhaps the most dramatic change to this monster is that it has four times as much health as its vanilla counterpart (12000 vs 3000); however, the "brain" portion of the Spider takes about 2.5 times more damage than normal. This, combined with the 50% increase in rocket direct hit, allows a skilled player to kill it faster than in Vanilla Doom. Another tactic, though very risky, has players attempt to rush towards the enemy and use chainsaw all the way until the demon is dead. In v20 the player can run in-between the robotic legs of the Spiderdemon, but there is the risk of being squished under them (akin to the Cyberdemon's stomp). When the Spiderdemon explodes upon death, its robotic legs fly wild and can damage any players or monsters who are near.
 * Decorative props, such as trees, hanging corpses and lights, can be destroyed. Destroying hanging corpses will occasionally reward the player with health, armor bonuses, pistol caskets or stimpacks that were hidden inside them. Players are advised to destroy them for this reason.Screenshot_Doom_20131224_190259.png
 * As of v19, brain pieces now scatter in walls after a headshot.
 * All moving entities now wade through liquids instead of walking on top of them (their sprite appears partially submerged), causing splashing sounds to play. The various liquid textures are also greatly enhanced.
 * Enemies randomly drop demon strength runes upon death, which act similarly to berserk packs (the only real difference being that they replenish only 10% of health, unlike the 100% health boost provided by the berserk pack).
 * Brutal Doom also has available downloads certain "mutators", or mods, that tweak the gameplay further; such as by changing the rifle back to a reskinned pistol, and giving the former humans the ability to speak and taunt the player.
 * (Prior to v19) Corpses can be mutilated upon death, should the player wish to prevent Archviles from resurrecting things or simply for the catharsis. Was temporarily removed in v19 because it caused bugs (this also prevents you from obtaining the Revenant and Mancubus weapons); It was re-added in v21.
 * Both the Cyberdemon's and Spider Mastermind's exploding death animations dealt heavy damage (or instant death) to anything near the explosion.

Previous and/or no longer applicable features

 * (Prior to v19), Commander Keen's head is replaced with that of infamous pop star Justin Bieber.
 * (Prior to v19) There was ammunition change such as having the bullets use 300 ammo (and 600 with the backpack) and the BFG expanding to 50 cells per shot. Removed in v19 because they were breaking compatibility with wads using DEHACKED.
 * (Prior to v19) The BFG9000 energy ball could fatally injure the player if it exploded too close (though this self-inflicted damage would be greatly reduced if the energy ball hit an enemy).
 * (In early versions) the Cyberdemon had the ability to launch grenades as well as rockets.
 * (In early versions) the Spider Mastermind possessed a BFG.
 * (In v18) The minigun's continuous fire produced a recoil which constantly pushed the player's aim upwards. This was corrected in v19.
 * (In v18) A dodge system was introduced, allowing some enemies (mostly the weaker ones, such as Zombies, Imps, Cacodemons and Lost Souls) to occasionally dash/roll/fly sideways to avoid projectile attacks. This was removed in v19 (except for Cacodemon and Lost Soul) but will be added in v20 as an optional mutator.
 * (Prior to v18) Firing hitscan-based weapons too close to walls and other solid surfaces dealt minor shrapnel damage to whatever was too close (namely players and zombies finding themselves on the wrong end of bullet spread in a narrow corridor).

Individual Weapon Details
The following weapon information are based on Brutal Doom v21.
 * Based on recent update August 25, 2018.
 * When dual wielding a gun, the alt-fire option will disappear and the max firing ammo of gun will be doubled. However, a gun's dual wielding can only be accessed when the player picks up two guns of the same type below.