Box art - Doom Eternal

Doom Eternal Fortress of Doom Installation Disks | How to unlock the original Doom

When exploring the Fortress of Doom in Doom Eternal, you’ll find an old computer containing a mystery. The first time you visit the Fortress, you’ll find that the first file has a readout that mentions “DOOM Installation,” along with a message that states, “You have ## of 14 disks installed.”

If you’re looking to play the original Doom in Doom Eternal, you’re in luck. This mystery computer in the Fortress of Doom will allow you to do just that. But how do you find the Doom Installation disks? Well, we’ve got the answer to that below.

Where do I find the Doom Installation disks in Doom Eternal?

It’s not immediately apparent where you have to go to find the 14 Doom installation disks in Doom Eternal. The computer itself isn’t any help, asking you to see a “user manual” that presumably doesn’t exist for more info.

Getting to install and play the original Doom is actually a bonus for nabbing a particular type of collectible throughout the game. When you get all 14 cheat code disks in the game, you’ll also unlock Doom 1 in the Fortress of Doom.

Fortunately, we’ve got all the cheat code disk locations in another guide. So, if you’re missing a disk and you’re stumped, check it out for some assistance.

Doom Eternal Fortress of Doom Unlock Original Doom

Can I play the original Doom in Doom Eternal?

The version of the original Doom that’s unlocked by collecting all the disks isn’t just a demo or a single level. You unlock the entire game once it’s installed at the Fortress of Doom.

The big question is which version of Doom do you get? Well, you get The Ultimate Doom, an expanded version of the classic FPS. That means you can play through all four episodes:

  • Knee-Deep in the Dead
  • The Shores of Hell
  • Inferno
  • Thy Flesh Consumed

Notably included is the fourth episode, which was added in The Ultimate Doom: Thy Flesh Consumed. So, you get to experience all of the first game for free. By playing the original Doom in Doom Eternal as Doomguy, you get some real Doomception going on.