Doom II: Hell on Earth/MAP08: Tricks and Traps

You start this map in an octagonal room, with exits in each of the eight directions. Two of them are locked, and most of them lead to paths that either have traps or surprises.

Technically, there are only three doors you need to enter. The first is the southern door with the cyberdemon, the second is the north-west door leading to the red key, and the third is the western exit.

North room
The northern room has one visible Sargent. If you attack him, you will alert up to 8 cacodemons that will appear from holes on the side of the room (and they will also appear if you run to the north to collect the plasma gun.)

Flipping the switch allows you to access a secret in the north-east room.

There are two teleporters in this room that become available if you otherwise block access to either the exit or red key room.

North-east room
The room provides a rocket launcher in plain sight. However, grabbing it will close the door behind you and build stairs to allow the demons to attack. These demons allow access to two switches. The east switch opens the entrance door, while the west switch opens the a secret to the north.

The secret leads to a soul sphere, and if you continue further north, backpacks. However, demons will be released behind you.

East room
The east room has a set of teleporters, which if used, leads a room of monsters. It contains specters and cacodemons, and if released from the center pillar, pain elementals.

South-east room
The south-east room contains a large quantity of imps, and a shotgun. However, the door closes behind you. To exit, jump into the imp pit, and flip the switch in the northern alcove. If desired, you can collect ammo from the southern alcove. Approach the western drop to teleport back to the room entrance.

South-west room
The south-west room contains a cacodemon guarding a chainsaw. Approach the chainsaw to release either a Baron of Hell or a second cacodemon. The second monster guards ammo and green armor.

Route to the exit
There are three mandatory rooms. The first is to the south, where a cyberdemon overlooks an army of Barons of Hell; the door will close behind you after a few seconds. To defeat enough of them, have the Cyberdemon fire its rockets into the crows and wait for the combat to finish. Collect the key in the alcove, and press the switch to reopen the door.

If you alert the Barons, they will try approach, and will also teleport into the central hub. However, there are a few invulnerability charges that can protect you.

The second room is to the northwest, and the entrance will lower into a slime pit as you approach the red key. In addition, Imps and a few other power enemies will lower from the ceiling. To escape, flip the switch on the left to raise the platform.

The final room is to the west of the hub. Enter, and run across platforms before they sink into the slime pit. In the final room, kill the demon, and exit the level.

Secrets

 * 1) After flipping the switch in the North room, open the door in the North-east room.  This leads to a soul sphere and backpack.
 * 2) The BFG is located in the east of the above secret, after the demons are released.
 * 3) In the eastern room, open the wall marked by the candle and enter the teleporter. This leads to a platform with a medikit and ammo.
 * 4) Within the same room, a wall in the north-east corner can be lowered by opening it.  It leads to invisibility.
 * 5) Within the same room, flip the switches on the north and south of the central pillar,  It releases monsters, but opens a secret door on the northern alcove.
 * 6) The same switches also open a secret door in the southern alcove.
 * 7) In the southwest room, reach the end of the corridor (just past the door that opens).  It contains ammo and green armor.