The Fortress of Doom is Doom Eternal’s hub area. Most of what is inaccessible at the start will unlock over time, but you can also unlock new areas with the Sentinel Batteries you find in each mission.
Using two Sentinel Batteries gives you access to areas with large question marks throughout the base. If you located these areas on your map, you’ll see that four Praetor Suit Points, two Modbots, and two Sentinel Crystals are locked away.
There are also other unaccounted for items: two Cheat Codes.
You can get one of them fairly early on, with the second only available near the end of the game. Below we’ll show you maps and detailed explanations for where to find these two hidden items in Doom Eternal.
Fortress of Doom Cheat Code locations
There are two cheat codes hidden on the Fortress of Doom.
Fortress of Doom // Cheat Code: All Runes
Using two Sentinel Batteries, you can unlock an area in the northeast region of the Fortress of Doom. Inside, you’ll find a new customizable skin.
Once inside the chamber that unlocks the original Praetor Suit, look for an exit out of the chamber through a hole in the wall to the left. Drop out of the hole and turn back to face the structure. Further down, look for a small opening containing the Cheat Code: All Runes.
Fortress of Doom // Cheat Code: Fully upgraded suit
[Warning: The explanation of this cheat code’s location contains spoilers for those reading this early in Doom Eternal’s campaign.]
This cheat code is only available near the end of the game.
Once Samuel Hayden is a part of your ship, and you have the sword, and you’re getting ready for the tail end of the game, you’ll notice this question mark above where the Crucible is located on your ship — just south of the control room.
There’s no way to reach it normally, but if you look at the top right of the room, you’ll see a red node you can shoot. Doing so will create a red jump pad in front of the Crucible that will launch you into an air duct above the question mark. Drop down and grab the Cheat Code: Fully upgraded suit.