This level occupies the map slot MAP12. For other maps which occupy this slot, see Category:MAP12.
MAP12: Entropy is the twelfth map of Alien Vendetta. The first few rooms were designed by Adam Windsor, with the rest of the level designed by Brad Spencer. It uses the music track "The Imp's Song" from Doom. It consists of three separate maps originally intended for a project to remake Doom II's levels to fit their titles. The three remade maps were: MAP01: Entryway (designed by Windsor,) MAP02: Underhalls (after the slow elevator in Entryway,) and MAP03: The Gantlet (after the teleporter in Underhalls.)
From the start, go through the big door, then swing around to your left and proceed through the smaller one. Open the brown wall in the next room to get some armor and health.
Exit the room secret 1 was in, and hug the wall to the left. There's a rusty patch on the silver wall nearby; open it to reveal a secret hallway. Open the grated wall in this passage to access an adjacent room with some shotgun ammo.
In the same early room secrets 1 and 2 were accessed from, there are two brown lifts. Lower the eastern one, and open the southern gray brick wall before the lift rises to reveal a secret room with a rocket launcher inside.
A bit further on in the level is a room with two columns made of lights, and a ceiling light rimmed with blue. One of the brick walls here has a green tinge to it; open it to get a couple of rockets.
While facing the blue door, head left (north) through the corridor until you reach a split in the path. Go left (west) and continue until you see an alcove high on the right (north) wall with some tall blue lights in it. Lower the wall beneath it like a lift, then ride it up and open the blue-light wall to get a berserk pack.
From secret 5, head straight east until you are forced to take a right. In here is a nukage pool with an isolated column on the far side. On the opposite side of the column is a skull facade; press the use key on it to lower the column, revealing a combat armor.
After passing through the teleporter behind the blue door, continue through the silver door into the next room. On the right-hand wall there is an inverted cross pattern; lower this wall to get a backpack.
In the hallway leading to the yellow keycard, there are some stairs leading down with a computer alcove on the right-hand side. Run from the landing of the stairs into the alcove. The right side of the computer panel opens, revealing a hidden teleporter.
After passing through the first teleporter within secret 8, open the center of the computer panel on the left to get a BFG. Take another couple of teleporters to exit this secret.
After opening the yellow door, pass through it and continue through the corridor until the walls on your left and right open up in ambush. Inside the right-hand area that opened, there is a wall with a yellow lightning bolt symbol on it; open it up to get a medikit.
From secret 10, continue through the "UAC"-marked door and you'll see another lightning bolt symbol on the wall in front of you. Open it up to get a rocket launcher.