Doom Eternal: Fortress of Doom collectable locations - and how to get the Unmaykr weapon

The Fortress of Doom is Doom Eternal's hub you visit between levels - and, with how laden the game is with things to find, it's no surprise there's some here to find too.

You can also find something here not available anywhere else - the ability to unlock the Unmaykr weapon.

If you're looking for other things to find in the game, our Doom Eternal secrets page can help

On this page:

Doom Eternal Fortress of Doom Cheat Code locations (2)

After unlocking the Original Praetor skin for your Doom Slayer (which requires two Sentinel Batteries, mind) get close to the window on the left. From the ledge, let yourself fall to scape and quickly dash towards to access the underneath area. Approach the '?' sign to unlock the "All Runes" cheat code.

Only after finishing Sentinel Prime, walk through the main corridor starting from the main hub of the fortress, getting close to where the secret weapon unlocked with Empyrean Keys is located. Pick up your rifle and use the scope (or just try to aim directly with a different weapon) to shoot small switch on one of the windows on the right. This will unlock a bouncing platform right behind you, which leads the slayer towards an air vent in the ceiling. Make your way through there and you'll appear right above the 'Fully Upgraded Suit' cheat code.

Doom Eternal Fortress of Doom Codex Entries locations (1)

Once you're done with Exultia, you'll be tasked to use a Sentinel Battery in order to unlock new sections inside the fortress. Among them there's the Slayer's own room, which is filled with funny references to past games, along with showcasing collectibles such as the toys you gathered throughout the story. Pay your room a visit and pick up 'The Fortress of Doom' codex entry.

Doom Eternal Fortress of Doom Modbot locations (2)

There are two additional Modbots to gather inside the fortress, each requiring you to use two Sentinel Batteries to unlock.

Doom Eternal Fortress of Doom Praetor Suit Point locations (5)

After Exultia, the main mission will lead you to pick up your first Praetor Suit Point.

There are four additional Praetor Suit Points to gather inside the fortress, each requiring you to use two Sentinel Batteries to unlock them.

Doom Eternal Fortress of Doom Sentinel Crystals locations (3)

After finishing Hell on Earth, you'll be able to pick up your first Sentinel Crystal on the right side of the navigator cabin. It's part of the main mission so you won't miss it.

There are two additional Sentinel Crystals to be found, requiring two Sentinel Batteries each.

Doom Eternal Fortress of Doom Unmaykr Weapon location

After gathering all Empyrean Keys, head towards the locked terminal inside the fortress. Once opened, this will reveal the Unmaykr, that secret weapon that first appeared on Doom 64. This will serve as an alternate option for your BFG weapon slot, using the same ammunition. Make sure to get this as early as possible, since it will definitely become of use during the later levels.

How to play the original Doom and Doom 2 in Doom Eternal's Fortress of Doom

Once you've found all cheat codes in Doom Eternal, return to your room in the fortress and interact with the computer. The original Doom is now available to play (including saving/loading).

There's another blank window on the side, which will ask for a code to reveal. If you write down FLYNNTAGGART you will also be able to play Doom II.

If you're still hunting for more collectables, our main Doom Eternal secrets hub page covers everything else to find in the game.