MAP28: The Absolution (Doom 64)

MAP28: The Absolution is the last level of Doom 64. The background music is the same heard in level 11, Terror Core. The layout is simple: You start off in a room containing all the weapons but the Chainsaw, including the Unmaker and a large amount of ammunition. After this, the marine pays the eternal price for the absolution of the UAC's sins as he lingers within Hell, ensuring the demons won't grasp for domination past the borders of their own domain ever again.

Walkthrough
Leaving the room (the door cannot be re-opened after leaving), you will enter a courtyard with a pillar-like object in the center and 3 small "rooms" which cannot be entered and have a switch each next to them. The focus of the map: survive an onslaught of enemies, and then fight the Mother demon boss. The key strategy will depend on whether or not you got the Demon Keys. The three unique switches are positioned north, east, and west of your position of entry to the courtyard.

The only way to activate the switches is with the keys (you do not lose them from your inventory). The more you have, the better your survival, since they close the doors of the demons' entry points.

Closing them all will greatly reduce the number of demons you have to fight, and killing what few stragglers remain will lower the center pillar.

If you had the three keys, this level shouldn't be too difficult. Grab the Invulnerability upgrade, head into the arena, and close off the teleports before too many monsters arrive. Use the rocket launcher to destroy any enemies that might have spawned into the arena. Once all enemies are dead, the Mother demon will present herself from the center pillars.

If you do not have any of the keys, this level will be far more difficult. Like the last tactics above, grab the Invulnerability and immediately use the Rocket Launcher for splash damage until Invulnerability is about to run out. Perferably, you want to take out all of the Pain Elementals first at this time to minimize the number of Lost Souls on the field. Once the Invulnerability runs out, you may to to fight more cautiously if you wish to use the Rocket Launcher to avoid an accidental blast on a nearby enemy like the Lost Soul, a wall, or pillar. You may also want to minimize the use of the Plasma-Cell based weapons like the BFG 9000 to reserve for the last part. With the amount of enemies on the field, monster infighting is going to happen a lot. The big exceptions are the Pain Elementals which is the first priority to kill; otherwise, the field will be infested with Lost Souls and the use of ammo increases greatly. Even if all Pain Elementals are gone, don't rely too much on the monster infighting because you want to still preserve your health, plus infighting will not happen against those of the same enemy type (i.e. Baron of Hell vs Baron of Hell).

Once all the enemies are cleared off or if the switches are activated, the Mother demon appears. The Mother demon has 2 attacks: flame trails that will launch you in the air and make it harder for you to control your movements and 4 simultaneously launched homing missiles that will do massive damage; while not deadly as Cyberdemon, they are much harder to dodge. To kill the Mother demon, use the fully-powered Unmaker to quickly kill her before she launches an attack. If your Unmaker is not fully powered, you are going to have to rely on the BFG 9000, so hope you saved enough ammo against her. Otherwise, you are going to have to rely on the rocket launcher which fortunately takes less rockets to kill versus the Cyberdemon due to the Mother demon not resisting splash damage. There is a central spot of the Mother demon's pillar that has a soulsphere that respawns either megaarmor, a megasphere, and then back to soulsphere so keep that in mind to make the fight against the Mother demon easier.

Secrets

 * There are no secrets in this level.