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Here are all the secrets in your Doom Eternal base

Doom Eternal Fortress of Doom Space Station Sentinel
(Image credit: id Software)
Rip and tear with some more Doom Eternal goodness

(Image credit: id Software)

Doom Eternal review: Our definitive verdict
Doom Eternal tips: Weather the steep difficulty curve
Doom Eternal Slayer Keys: Unlock the optional encounters
Doom Eternal Runes: Give Doomguy the edge
Doom Eternal settings: Kill in high-res glory
Doom Eternal Battlemode: Tips for victory
Doom Eternal Marauder: Beat the fallen Night Sentinel
Doom Eternal Super Gore Nest: Find every collectible
Doom Eternal difficulty: Choose the setting that suits you 

Look for all the Doom Eternal base secrets? This hub area is the place you'll recuperate between missions, and it's filled with goodies. Inside your floating castle you'll unlock new weapons and grenades, restore power to rooms containing modbots and Praetor Suit points, and collect other stylish wares. Collectibles you've unearthed throughout the campaign are also stored here for you to appreciate in the Slayer's quarters.

If you want to see your demon toys meticulously displayed on a tidy shelf, rock out to some classic tracks, or maybe just marvel at the Slayer's slightly gross, albeit unapologetically metal, instruments, you're in the right place. So, let's get down to how you can complete your cheat code collection and solve the mystery of those password-protected files on the Slayer's computer. Prime yourself for spoilers, naturally, as we cover all the Doom Eternal Fortress of Doom base secrets. 

All Fortress of Doom base secrets

Cheat codes

There are two Doom Eternal cheat codes located in the Fortress of Doom and both are relatively easy to find:

  • All Runes: This unlocks all nine Runes. Start your search by venturing to one of the Fortress of Doom's outbuildings, with a couple of Sentinel Batteries in hand. Starting in the main area in the Fortress, exit at the back of the room and take the stairs down. Head through the large door in the middle and then bear right to take the doors that lead outside. Slot your Sentinel Batteries to access the building, and drop down through the hole on the left onto the ledge below to acquire the code. 
  • Fully Upgraded Suit: This unlocks all Praetor Suit points. Inside the Fortress, walk to the room with the stained-glass windows and shoot the red target on the middle window on the right side. This reveals a red jump pad with which you can reach a ledge in the ceiling. If you can't see a red target on the window you may have arrived a little too early. If this is the case, revisit the room later after completing a few more missions to grab the code.

Computer puzzle

You need to make your way to the Slayer's bedroom for this one. Perched on his desk is an old computer with two mysterious files on display. The first file is the original Doom game which you can unlock by completing the campaign and collecting all cheat codes. The second file is password protected. Enter the Doom Eternal computer code FLYNNTAGGART in the terminal to unlock the Doom II game file. 

(Image credit: id Software)

Sentinel batteries

Sentinel Batteries are found individually across Doom Eternal's missions, but pairing them gets you the good stuff. The Fortress of Doom houses a number of locked rooms that require you to donate two batteries to restore power and access what's inside. 

In addition to the cheat code outside and a special reward from completing all six Slayer Gates, here are all the other things you can find:

  • Classic skin: In the large room at the back of the Fortress, directly opposite the main room. 
  • Praetor skin: Located in the outbuilding on the right side.
  • Sentinel skin: Located in the outbuilding on the left side.
  • Two Modbots: On the floor below the Classic skin.
  • Four Praetor Suit points: Two on the floor below the Classic skin, and two on the floor below the Slayer's room.
  • Two Sentinel Shards: On the floor below the Modbots.