You'll discover the Doom Eternal computer password exists not long after you get to explore the Fortress of Doom. Finding out what the code actually is though is another matter entirely. It's not, as you might expect, for entering old school Doom cheat codes, but instead you'll need to know a far more obscure Easter egg reference to unlock what's behind it.
What is the Doom Eternal computer password?
To access what's behind the Doom Eternal computer password you'll need to type in the code 'FLYNNTAGGART'. Which, for those not up on their Doom lore, is the name of Doom Guy in the old 1995 novels, and one of the many possible but unconfirmed names for the main character. Put that in the computer and you'll unlock Doom 2.
And that, for now, is all you can do. When I try and click on Doom 2 the game hard crashes back to my desktop and it sounds like it's doing the same for a few other people. Presumably Doom 2 hasn't actually been added to the game properly yet. It does at least play this this loading bar animation when you go near it now which I don't remember before. How long do downloads take in space I wonder?