Level 5: Phobos Lab

Start by crossing the slime pit and entering the opening opposite.

Clear out Shotgun Guys and Imps. If on Ultra Violence, defeat the Nightmare Spectre here.

Head right until you reach a wall, then turn left into an opening.

Walk straight; a bridge will rise. Turn around, follow the right wall to a staircase, and ascend.

At the top, eliminate Zombiemen and collect the Medikit.

Destroy the nearby barrel to reveal a secret door. Enter to find a Shotgun and a Box of Shotgun Shells.

Turn around, go through the opening to the right, and cross the bridge to the next opening.

In this hall, defeat Shotgun Guys and Imps, then proceed to the Yellow Key.

After obtaining the Yellow Key, turn around and leave the room.

Drop into the pit below. Locate the blood corpse in front of a wall; this indicates a hidden door. Open it and proceed.

In this secret room, collect the MegaArmor, Rocket Launcher, and a Box of Rockets.

Go through the opening to the right and walk forward. A wall will open; pass through it.

Back inside, open the door to your right and enter.

Eliminate Zombiemen and Shotgun Guys to your left and across from you.

Follow the left wall to the Yellow Door. Open it and go through.

Walk forward and drop to the floor below.

Defeat the Demons, Imps, and Shotgun Guys ahead.

Head right, following the hall until a large slime pool appears to your left.

Cross the slime pool and activate the switch on the other side. This will lower pillars, revealing Imps and Zombiemen; defeat them.

Enter the opening with the Medikit across from the slime pit.

Press the indicated button on the wall to open it. Collect the hidden Radiation Suit.

Open the secret door to the left to find the Chainsaw.

Open the door in front of you to exit outside. Collect the Soulsphere and return inside.

Retrace your steps back to the lift, eliminating any Imps, Demons, or Shotgun Guys encountered.

At the lift, descend, board it, and ride it to the top.

Exit this room and go through the opening opposite.

Ascend the stairs, defeating any Shotgun Guys or Demons in your path.

At the top, enter the opening to the left.

Clear out the Imps, then head into the opening to your right.

Defeat the Shotgun Guys in this room and find a switch. Activate it to open a wall like a door; proceed through.

Follow this hallway until you reach the Blue Key, eliminating all Imps.

Grab the Blue Key.

In this room, defeat the Zombiemen and Imps, then activate the switch.

Turn around and descend the stairs in front of you.

Open the Blue Door and go through.

Navigate the dark hallway. Follow either the right or left wall to the exit door, defeating any Shotgun Guys or Spectres. Note that Shotgun Guys glow when they fire.

Open the exit door and enter.

On high skill levels, defeat the Demons here.

Finally, hit the exit switch to complete the level.