- This level occupies the map slot MAP23. For other maps which occupy this slot, see Category:MAP23.
Map 23: Unholy Temple, is the third last level in Doom 64. The level is best described as eerie for it's very dark atmosphere. The marine has no choice but to traverse through the unholy architecture within the nethermost parts of Hell. The music is the same as MAP07: Research Lab.
The sky is dark with forever burning green fire, signifying how deep you are in Hell. You start off in a small moat that surrounds the central temple that vaguely resembles a pyramid. On top, you can barely see Hell Knights and Spectres, some active right after you start. In the moat, there are several Arachnotrons that are luckily encoutered one by one. There is a teleport at the end of the moat that takes you to the "second" floor of the temple. After defeating the Spectres and Hell Knights, you climb up the temple to turn on the switch which will you go inside the temple. Inside the temple are several corpses and two Barons of Hell waiting to ambush you as soon as you step in. Continuing on there is a room with a couple of Arachnotrons also waiting to ambush you as soon as you take the megaarmor.
Once you collect all three skull keys you need to enter a room to input a code-like sequence that corresponds to the colour of a key. The reason for this is because through-out the level, there are three locked doors that have the colour of the keys etched in right beside it. Depending on the order from left-to-right is what you must enter in the code room. If you get the code wrong, one of the most scariest traps will occur; the outer part of the room will lower exceptionally quickly, and a Hell Knight will spawn moments later, and you must kill it if you want to proceed any further. This can be extremely scary if you are standing right next to where the Hell Knight spawns. If you get it right, the room will unlock and you must push a button that will remove one barrier from the exit, hence the reason why you must do this. Once you removed all barriers, you will be able to exit to the penultimate level No Escape.
- The first time you go up an elevator in this level, turn around. You should see a platform with a bunch of cell packs and an Unmaker resting on it. Shoot the orange tile on the wall behind the Unmaker, and the platform will lower all the way down to the water, allowing you to get its contents.
- Eventually you'll come to a big cross shaped room with the yellow key. On the blank wall that is directly opposite of the Exit, is a secret wall. Open it to reveal a cache of rockets.
- You will come to an area that has a Soul sphere on a ledge, and a pillar in the middle with three colored switches on it. The side of the pillar without a switch has a fake wall. Walk through, and you will teleport to the ledge with the Soul sphere.