E1M7: Halls of Madness (Strange Aeons)
When you step forward, you are administered a Berserk Pack just as your cell door opens. Rush outside and splatter the mobs of monsters in the courtyard. You will find the yellow keycard in the psychologist's house on the hilltop, but grabbing it releases more monsters in the asylum.
Follow the asylum halls right from the entrance to find the yellow door, which protects the red keycard. The cells open when you approach the keycard, releasing its inhabitants. Passing through the red door has a similar effect. When you get the red keycard you may want to take a detour to the house on the hill and help yourself to its armory.
Beyond the red door is a teleport that leads to what's left of the shower room, and the blue keycard. Jumping into the aether here will drop you into a Flayworm ambush instead of the courtyard. Return to the house on the hill and go through the blue door to the exit.
Other points of interest
Check behind the house for a Computer Map.
On the way to the yellow door, there is a bisected office. Drop off the ledge to the narrow cliff, and follow it to a hidden teleport. It takes you to another Berserk Pack and a cache of Rockets.
In the house on the hill, look back toward your spawn point from the large windows to find a small green switch on the wall of the asylum. Shoot it to lower the Rage Sphere.
In the red door hallway, one of the padded cells doesn't have a floor drain. Enter that cell for an Ammo Sphere.
Just beyond the blue door is a fusebox. Shoot it to lower the bookcase in the living room, revealing a wall switch. Flip the switch and dash to the cell nextdoor to your spawn point before it closes: it contains a Soul Sphere.
Jump off the cliff by the exit slipgate for the third Berserk Pack. This is mainly for an emergency heal and to get 100% items.
Inspiration and development
This is the third incarnation of this map. Two other versions are featured in his obscure indie games Shudder and Nightmare Toys.