MAP29: Outpost Omega (Doom 64)

MAP29: Outpost Omega is the twenty-ninth map of Doom 64 and the first secret level. Should this level be undertaken right after MAP04: Holding Area this is where the player will first come across Mancubi and Pain Elementals. The level also contains the first of the strange artifacts known as Demon Keys which upgrade the Unmaker, which can also be found in this level. The music for this level is the same as MAP05: Tech Center.

The Demon Key
In order to get the Demon Key, a hidden red key card must be acquired. By the entrance to the room with the four cages not long after the starting room there are techy microchip boards in the walls. The board on the right (looking in) is a secret switch that will open a hidden door on the opposite end of the cage room, revealing the red key temporarily. Run across the room and pick it up.

After getting the red key, the Demon Key and the Unmaker can be obtained in the tall multi-chambered room which also houses the yellow key. You traverse the room by leaping from available platforms or dropping down levels to reach the bottom. There are teleporters at the bottom which will send you back up to start over, so you can explore as much as you need. After obtaining the yellow key, there is a switch in the room guarded by an imp or hell knight on the mid level. Hit the switch and a platform will temporarily lower back the way you came. Jump back to the lowered platform quickly and ride it up. This will reveal a switch on the opposite wall which can be shot to be activated. That switch will permenantly lower a new platform near the original mid-level switch. From there, one of the nearby walls is a secret that lowers when activated, revealing the Unmaker. After you have picked up the Unmaker, shoot the switch which is visible from across the Unmaker's platform. Then head back to the first shootable switch and strike it again to further permenantly lower the platform, which will reveal the red key door. Behind the red key door is the first Demon Key.