E1M8: Phobos Anomaly is the boss level of Knee-Deep in the Dead. Designed by Tom Hall and finished by Sandy Petersen, and the par time (cannot be seen in official Doom source port due to hidden intermission screen) is :30.
Press the switch in front of you. Turn left, then forward, until you come to a door. Open it, follow the passage to a switch, press it to lower the platform, then ride it up. Once you enter the red floor room, you will invoke 2 Barons of Hell. Kill both of them, and once they die, jump into the now-accessible courtyard. At the north is a building with a switch. Press the switch to raise stairs to a teleporter. Take it to a damaging floor of type 11 - once you die the level ends. That makes sense because the entrance to The Shores of Hell, the next episode, is evil because it is HELL!
Other points of interest:
The east of the demon room with barrels you can find a lift that rises as you step on it. Ride it up to access a box of bullets, ten stimpacks, and a computer area map. Once you step on the lift from the ledge, it will lower BACK. If you leave the lift while it is fully lowered, however, it will rise without you, blocking the ledge permanently, so you should fall down before it fully lowers.
If you enter the courtyard, then you cannot return to the previous map.
The right Baron alcove has a secret door to the east. Open it to access a switch that lowers the platform to the red floor room. (The room is not needed for 100% secrets)
There is a staircase taking you to the door. To the right of it is one different-texture wall. Open it to access a soul sphere.