Map 11: Circle of Death

Start on the circular ledge. Immediately deal with the Chaingunner and two Shotgunners on the platform ahead, ideally with a rocket.

Proceed around the circular ledge anticlockwise, eliminating all hit-scanner enemies. Watch out for Cacodemons, Lost Souls, and Imps firing from ledges, especially a high one to the north-east and one to the south-east near an Invisibility Orb.

A staircase leading down to a Shotgun is located south of your starting point, accessible through an opening between pillars.

At the northern part of the map, shoot Lost Souls from a caged window. To the right, a Revenant hides behind a wooden pillar with a skull switch; eliminate it with rockets.

Once all hit-scanners on the circular ledge are dead, move to the eastern part. Be ready to quickly kill Shotgunners near the walkway and opening with green torches.

As you approach the stairs in this eastern section, shoot down Imps on either side. A third, hidden Imp is in the south-east corner within a fake wall, near a green torch. A Supercharge is hidden inside this fake wall (not a secret).

Collect extra ammo and a green Armor vest from the sides of the stairs.

Head up the stairs to a gravelly area with trees. Kill the Arachnotrons on your left and right, luring them to the staircase if needed.

Upon reaching the top of the stairs, an elevator to the right (southern side) will lower. Kill the Imp patrolling on it. Before it rises, get on the elevator to reach a high recess containing a Chaingun and Armor Bonuses.

Examine the wall with a different texture (pipes) in this recess to reveal a hidden opening [SECRET 1/3].

Enter the opening and follow the passage to drop onto a ledge south-west of your starting position. Claim the Partial Invisibility Orb.

Quickly run to the low ledge on the southern part of the circular ledge (where the Shotgun was found) and go back up the stairs.

Return to the gravel-floored room and take either staircase on the left or right to a wood-panelled corridor at the top. Shoot down the hit-scanner enemies here. Extra ammo can be found on ledges beside the staircases.

At the back of the corridor, an opening leads to a room containing the Blue Key Card. Before entering, shoot down more Imps.

In the room with the Blue Key, a wooden column hides a trap. As you approach the Blue Key, the column will rise, revealing an Arch-Vile. Use the SSG or Plasma Gun, and take cover behind the doorway to avoid its fire attack. Kill it quickly to prevent monster resurrection.

After defeating the Arch-Vile, safely grab the Blue Key and a Plasma Gun from behind the column.

Return to the circular ledge and proceed to the west side to find the blue door.

Enter the corridor beyond the blue door. Deal with the Hell Knight, Pain Elemental, and any remaining hit-scanners.

Hit the skull switch on the wooden column. A ledge with Health Bonuses will start raising outside the window. Wait for it to finish raising before proceeding.