E3M9: Warrens (Doom)

E3M9: Warrens is the secret map of Inferno in Doom and can be accessed from E3M6: Mt. Erebus. It is based on E3M1: Hell Keep, and is similar until the natural end of E3M1, at which point the player must retrace his steps. It uses the music track "Hiding the Secrets". The par time is 2:15.

Overview
On entering the level, the player becomes aware that the scenery is familiar. The map is identical to E3M1 until the player reaches the area which formed the exit of this map.

The player is suddenly confronted with a Cyberdemon in place of the level exit (recalling the Tower of Babel). From this point onwards, sections of the map have opened up to reveal new regions and more enemies. The player must retrace their steps to beginning in order to find the true exit.

Walkthrough
Activate the lift and open the door, then take the shotgun,you must be quick because the bridge will descend. Open the door and go into the corridor. Go outside and stand in the Teleporter. Now,the level's structure will change. The wall will descend, pick up the rockets and prepare to fight against a cyberdemon. After killing it go back to level's beginning. Go into the new corridor and you'll be teleported into new corridor. Pick up the red key and open the red door and stand over the teleporter to finish the level.

Official

 * 1) In the same place as in E3M1: Open the wall on the left in the room before the fake exit for a rocket launcher.  (However, unlike E3M1, this rocket launcher is not available on Ultra-Violence mode and above.)

Non-official

 * 1) At the start kill all imps and cacodemon(s) then turn left and you will see a bridge with a shotgun in the middle. When you walk on the bridge it starts to sink into the lava, so quickly run to the other side of it and kill the imp(s) (that not appear(s) on easy skill). Once you have gone through the fake exit go back to the location where the other end of the bridge used to be (where you collected the box of shells) and jump in the lava, look right and keep walking until you see a radiation suit and a BFG 9000.

Bugs
Two "hanging leg" decorations (Things 80 and 82) have no flags set for any of the difficulty classes, so they do not actually appear in the level.

It is possible to lock yourself out of the first room by pressing the button to lower the first door in the level and then quickly running through the door before it closes. This will prevent you from beating the level. This bug is not present on E3M1; it is possible on this level and not E3M1 because the ceiling of the sectors either side of the door on E3M9 are higher than they are on E3M1. (It would not exist anyways in E3M1, however, because you do not need to ever return to the starting outdoor area after leaving it, thus being trapped inside would not prevent completion.)

In the stone courtyard with the imps, if you walk down to the dirt ground and look back through the open door, a small HOM is visible.

As with E3M1, the walls of the main red building at the start look paper-thin when viewed from either side. So too do the southern walls of the Cyberdemon room. In addition, the wall above the doorway to the collapsing bridge is paper-thin and causes a perspective glitch when viewed from the outside.

Records
The Compet-N records for the map are: