Found an easter egg.

The maintenance access door at the top of the tower district area has the access code 0451, just like the running reference from the Deus Ex series I'm assuming it refers to the book Fahrenheit 451 with appropriate dialog around that area to back it up. This game is so amazing, both the gameplay and story so far are far better than Bastion, and that's saying something.

@alucitary The code 0451 does refer to the book Fahrenheit 451, and it started with Looking Glass studio's games, whether or not started with the original System Shock, I have not done my research. As someone who has only played games for 15 years, my first contact with this code was in the original Bioshock, Deus EX Human Revolution and Gone Home also include it as the first code. I seem to remember it from Dishonered and like Transistor Bioshock Infinite include the code just to the heck of it.

It's both a reference to Fahrenheit 451 and Looking Glass. Looking Glass had it as the first entry code in every single game they made, and that tradition continued when the studio folded and key talent went elsewhere. Hence why it pops up in BioShock, Deus Ex, et cetera et cetera.