Plasma gun/Doom



"Plasma Rifles shoot multiple rounds of plasma energy - frying some demon butt!" ― Doom instruction manual

The Plasma Gun (also known as the Plasma Rifle in the game manuals and help screen) is a futuristic weapon with a barrel that roughly resembles an accordion, which fires blue and white bursts of plasma. It shares the player's stock of cells with the BFG9000 as a source of ammo.

The Plasma Gun first appears in a secret area of the very first level of the second episode, E2M1: Deimos Anomaly, and happens to appear in every level of The Shores of Hell, except for the Tower of Babel level. It first appears in a non-secret area in the fifth level, E2M5: Command Center. When picked up, it contains the equivalent ammo of 2 cells (totaling 40 units of energy, or 80 on the "I'm too young to die" and "Nightmare!" skill levels).

Combat characteristics
When the trigger is pulled, it'll fire rapidly like a machine gun, shooting small blue-white balls of plasma. Each plasma projectile inflicts 5-40 points of damage. The rate of continuous fire is one burst every 3 tics (about 0.086 seconds). However, there is a pause of 21 tics (0.6 seconds) when the trigger is released before the weapon can be fired again.

Tactical analysis
Due to its high damage rate (three times that of the Chaingun), the plasma gun is devastating against nearly any single opponent. A continuous barrage will stop an Arachnotron in its tracks, and even reduce a Baron of Hell to about half its normal movement speed and attack frequency. The Plasma Gun is also effective against large groups of weaker enemies (charging enemies like Demon), it can stop them all before they reach the player. Attacking monsters from long ranges can be inefficient, however, as enemies tend to move too much for the bursts to be accurate; it is also difficult to use against flying monsters in open areas, as the first few hits push the enemy rapidly backward and often to one side of the stream. A good tactic to counteract this, and avoid wasting ammo, is to fire the Plasma Gun in short bursts. Otherwise, it is a very powerful weapon that can be considered the jack-of-all trades.

Although the plasma gun does not inflict blast damage, firing it in close quarters demands a certain amount of concentration owing to horizontal auto-aim, which may steer its projectiles right into a wall if the nearest monster is not directly in front of the player. For example, using the plasma gun on the Cyberdemon in E4M2: Perfect Hatred, without placing the player in its line of sight, requires aiming at a point slightly to the monster's left. The plasma gun can also be used to light up dark places.

Data

 * 1) This table assumes that all calls to P_Random for damage, pain chance, impact animations, backfire checks, and muzzle lighting are consecutive. In real play, this is never the case: counterattacks and AI pathfinding must be handled, and of course the map may contain additional moving monsters and other randomized phenomena (such as flickering lights). It is also assumed that all projectiles are launched at nearly the same range, so that the various procedures call P_Random in the same sequence each time. Any resulting errors are probably toward the single-shot average, as they introduce noise into the correlation between the indices of "consecutive" calls.
 * 2) Assumes that direct hits are possible, which does not occur in any stock map.

Appearance statistics
The IWADs contain the following numbers of plasma guns: