MAP12: Entryway to the Worlds of the Ancients (Perdition's Gate)

MAP12: Entryway to the Worlds of the Ancients is the twelfth map of Perdition's Gate.

Plot: ''You step off the teleporter pad and see what appears to be a structure floating in space. You have no way back. Time to find out where you are.''

Walkthrough
There’s nothing of interest in this floating structure, so head straight to the teleporter in the south west corner to be taken to the level proper.

Shoot the Demon when you land and head up the stairs where you will find a large number of zombies and Imp's approaching. At the top of the stairs, take a right to a T junction where you need to take the right turn into a brown brick area. Though you might catch the attention from some of the bad guys down the left corridor as you do.

You will be presented with two sets of stairs almost immediately, one going down into a pit, the other going up to a ledge that runs around the edge of said pit. The end of the ledge and the pit both have switches you need to press to raise platforms. The switch in the pit can be found on the north side and will raise a bridge to the maps red key, whilst the switch down the end of the ledge will raise a structure in the pit allowing you to ultimately reach the blue key. Note the blue bars next to the later switch.

With both switches pressed, head back toward the teleporter you entered the map from, but instead of going down the stairs to it, keep going (i.e. you went right at the top of the stairs earlier, now you are taking the other route). Ultimately you will find a Rocket Launcher and a door.

Open the door to reveal a water filled area and a wooden bridge that leads across it to the red key (you raised this earlier). Red key in possession head to the south west corner of this area to find the red bars. Note the bridge extending to the yellow door on the west side of this area.

Open them and head up the stairs, watching for the bad guys that teleport into the water area behind you and use the teleporter at the top to enter a new brown area that when you follow round leads you to a ledge overlooking the already visited brown pit. From here you can jump onto the structure you created earlier and use it to reach another ledge over the other side, where you can find the blue key.

Head to the blue bars and grab the yellow key behind them. Finally head back to the water area, open the yellow door, behind which you will find the exit around the corner.

Secrets

 * 1) Just the one secret area on this map, though two of the sectors inside it are marked as secret. When you teleport into the map properly, head up the stairs and take a right as you do in the walkthrough. But instead of heading right into the brown area, head left one segment and press the right wall (the wall without the horizontal pipes) to reveal some stairs leading down to a hidden room. In here you can find a BFG9000 and computer map. (sector 71)
 * 2) In secret #1 you'll also find a switch that lowers an arguably unneeded platform that takes you back up the corridor (unneeded because you can just go back up the stairs you came down to enter this room). (sector 112)

Current records
The records for the map at the Doomed Speed Demos Archive are:

Things
This level contains the following numbers of things per skill level: