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. 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.

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 (tested on the Collector's Edition of Doom and also on the Xbox 360 Live Arcade version).

Walkthrough
Hit the switch in front of you. When the platform lowers, head straight to the door and hit the switch to the left of it. The door will open. Go through the opening to the right, and open the door. In this room, open the door to the right. Now, open the door at the end of this hallway. In this room, open the door across from us, and kill the Imps inside. The secret to the left of the exit door is still here. Open the secret wall and get the stuff. Now go through the exit door and step on the exit teleporter. Hey! The wall in front of us is lowering! Get to the other end of the room, grab the blue skull key, avoiding the Cyberdemon in here (you don't need to kill it, don't bother). If you can, grab all the new goodies in here, and when you are done, backtrack to the starting room, avoiding any new appearing enemies.

In the starting room is a new alcove. Take out your BFG, and go through the alcove. Sooner or later, you'll teleport. When you do, take that BFG and kill the Cacodemons in front of you. If you have enough ammo, use it to kill the Shotgun Guys that will ambush you from both the right and left. From where the Cacodemons were, go left and grab the red skull key. Turn around, go straight, and when you get to where the Cacodemons were, go left, and exit this room back into the starting room. Go to the door, hit the right switch (it is a Red Door, and you may need to hit it a couple of times), and go inside, through the exit teleporter.

Official

 * 1) In the same place as in E3M1: Open the wall on the left in the room before the fake exit.

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. Once you have gone through the fake exit go back to the location where the bridge used to be 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.

Records
The Compet-N records for the map are: