0451 is a series of easter eggs most likely started by Warren Spector and Looks Glass' System Shock in 1994. It is often believed to be a reference to a book Fahrenheit 451, but according to Warren, its origin is way more basic.

"Many think it's a reference to Fahrenheit 451, but it was actually the key-code to get into the Looking Glass offices in Cambridge."

0451 Vault - Bioshock 2 (2017)


Highly anticipated sequel to Bioshock, also featured 451 easter egg as a code to the first secured door you can encounter, although reversed to 1540.

0451 Vault - Dishonored 2 (2016)



Just like in first game, this one is also for the safe. This time however, it’s very possible, you can miss the safe it’s for, as it’s a bit off the way. It’s in the building on the left side of a street in the Dunwall Streets level. Code is hidden behind the painting, that you steal.

0451 Vault - Prey (2017)



So reboot of Prey tried in many ways be like Bioshock and System Shock and whilst it was a bit of hit and miss, it did also feature 0451 easter egg.

Also, special shoutouts to 0451 speedrunning team and especially to CoolsVilla for providing the screenshots.

0451 Vault - Dishonored (2012)


Dishonored also features a 451 reference. This code, hidden in sewers leading out of the prision is hidden behind some whisky and opens the first safe in the game.

0451 Vault - System Shock 2 (1999)


Oddly enough, while 451 appeared first in System Shock (1994), people mostly remember it for being in Deus Ex. System Shock 2, being a sequel to System Shock obviously had to have featured it in some form. It’s a bit of a variation on the code, but it’s still good old 451. And it’s even a door code.

0451 Vault - System Shock (1994)


Probably the first instance of 451.

0451 Vault - BioShock (2007)


It’s a spiritual successor to System Shock… or at least it tries to be, so naturally it has to reference 451 - again, as a door code.

0451 Vault - Alien: Isolation (2014)


Creative Assembly also decided to implement that easter egg as a door code.

0451 Vault - Deus Ex Mankind Dividied (2016)


Another Deus Ex, another 451 reference. This time, again - as a first door code ever used.

0451 Vault - Deus Ex The Fall (2013)


Even that crappy game with Deus Ex in the title had used it.

0451 Vault - Deus Ex: Human Revolution - The Missing Link (2011)


I actually don’t know, if the code mentioned in any pocket secretaries. Doesn’t matter though, as trying it on the very first door is going to open it.

0451 Vault - Deus Ex: Human Revolution (2011)


It was a Deus Ex game trying to rekindle love for Deus Ex series, so obviously it had to have 0451 as a first code ever used.

0451 Vault - Deus Ex Invisible War (2003)


This may be the worst of Deus Exs, but it did have 451 reference as well. Our protagonist’s appartement number is 451.

0451 Vault - Deus Ex (2000)


I’d say the game that started the easter egg series, but that’d be a lie, as there have been many games featuring 451 as we will see in the future. We do know however, it’s directly inspired by Fahrenheit 451 by Ray Bradbury.