Map 17: Tenements

Head across the slime path, use SSG to eliminate hit-scanners to the right.

Use rockets on enemies in high caged windows on both sides of the path.

Return to where you killed the hit-scanners, examine the wall behind them to open a window. Shoot Spectres and a Hell Knight in the opposite room from this vantage point. Dodge the Hell Knight's projectiles.

Turn around and head west down a zigzagging platform to a narrow ledge. Collect the Red Key Card and Medikits.

Be aware of traps: the third step down seals a door behind you for 30 seconds. Stepping on the ledge to get the key reveals Imps, and opens side walls revealing Cacodemons and hit-scanners. Use BFG if available to clear Imps as they appear.

Drop into the blood pit to the right of the zigzag platform. Find the corner of a red teleporter and step on it to return to the first room.

Wait for the door to re-open after 30 seconds. Eliminate Cacodemons that have entered the room, then hit-scanners in the windows.

Drop back into the blood pit and take the white teleporter to reach the window ledge where enemies were. Collect dropped weapons and a Medikit.

Take the red teleporter back to the entrance. Go up the staircase to the right, leading to the red door.

Before the red door, shoot Spectres through the caged window on the right. Enter the room, grab Medikits, Health Bonuses, and Green Armor if needed. Flip the switch on the wall.

Exit the room, go down the stairs, and up the opposite staircase. Collect items in this room.

Step on the lift with the Shotgun Shell Box, then hit the switch to be lowered into the wood-panelled room.

Grab the Berserk pack and follow the lit passage at the back to another switch. Activate it to access another lift.

In the new room, hit the wall switch to your left, then the gargoyle head switch to create an opening leading back to the slime pit starting area. Run through to land on the path.

Turn right. The door ahead with white lighting panels is now open. Head for the east opening.

Shoot Imps, a Shotgunner, and a Chaingunner in the narrow passage.

Go to the northern part of the open area (yellow skull columns) and shoot enemies through the bars if you have Chaingun ammo.

At the end of the east passage, look through the cage window to your left to see a Revenant on a high ledge with the Blue Key Card. Eliminate it with the Plasma Gun or Chaingun.

Deal with Shotgunners patrolling staircases at the end of the passage by luring them out and retreating to the passage to kill them safely.

Take the left stairs (leading to the Blue Key). A slime pit blocks access. Examine the red torch in the corner to reveal an opening in the wall to the right.

Fire at a barrel from a safe distance to trigger a chain reaction, killing enemies in the room at the top of the staircase.

Head up the staircase, collect dropped Shotguns, a Box of Bullets, and Megaarmor.

Hit the lion head switch on the wall. Look out the opening to your right to see a bridge raise over a slime pit.

Cross the bridge. As soon as you step on the ledge at the end, quickly turn around and head back to the opposite side.