Kill them all

Kill them all or is a Single Player level. This level consists of a single room with a lot of Monsters, similar to the slaughter maps from Doom.

Walkthrough
Proceed forward to collect the Super Nailgun. Turn right, then head to your right to collect the Shells. Continue going right while moving to your left to collect another set of Shells, then turn around. Head towards the upper left corner of the room to collect the Double-Barrelled Shotgun. Head diagonally to your right to collect the Shells. Turn around, then cross to the middle of the room while killing the Ogre. Turn left to look into the room; the rest of the level is rather symmetrical in design. At the far ends are 4 Zombies to ignore for the time being. 2 are on each nearer side, while the other set of 2 are past a Radioactive Container. Kill the 3 Grunts in the line straight ahead, 1 to your left, 1 to your right, and 1 straight ahead at the base of a mound. Proceed forward towards the mound to collect the Nails. Kill the 2 Knights, 1 to your left, and 1 to your right, in the area between the Grunts. Head up the slope to collect the Quad Damage.

Kill the 2 Shamblers straight ahead, both standing beside a pillar of Lava, and the Rottweiler between them. Turn left to kill a Fiend and Scrag straight ahead and an Ogre to your right. Proceed forward to collect the Nails, then turn around. Continue forward kill another Fiend and Scrag straight ahead and another Ogre to your left. Collect the Nails straight ahead, before the Radioactive Container. Use the Quad Damage to eliminate the 4 Zombies you previously ignored. Look towards the Lava pillar, then head towards it to collect the Nails. Turn left to kill the Grunt near the far side of the room, then fire upon the Radioactive Container to your right to kill another Grunt. Turn around to kill a Grunt to your left, then fire upon the Radioactive Container to your left to kill another Grunt. Look towards the Lava pillar once more, straight ahead are a series of two Radioactive Containers. Another two Radioactive Containers exist to the sides, 1 on each side. Hitting these outer Radioactive Containers can kill a Grunt and Rottweiler standing beside them, or two Grunts and 2 Rottweilers. Head to your left to collect the Rockets, then turn right to look into the room. Head towards the middle of the room while killing the 2 Fiends straight ahead to collect a Rocket Launcher. Continue forward to collect the Rockets.