Skip to main content
If you click on a link and make a purchase we may receive a small commission. Read our editorial policy.

One Redfall easter egg is a joke that's been running for three decades

How a nondescript door code survived studio closures through sheer force of imitation.

If Looking Glass Studios had survived until this day, its premises would be the least secure in the US games industry. The legendary developer secreted the door code to its office into the first level of System Shock – and ever since, the numbers 0451 have become a calling card for those who share Looking Glass’s immersive sim values; studios that tap into System Shock’s deep worldbuilding, dense level design, and reactive simulation.

Redfall is the latest to pay homage, but follows nearly 30 years of riffs and twists on the code that first allowed you access to Citadel space station’s healing suite. We’ve collated some of the most inventive and memorable below, and won’t even ask you to crack a combination lock to see ‘em.


Deus Ex

Classic, no notes.

Ion Storm Austin’s beloved spy story arrived half a decade after System Shock, yet was many players’ first introduction to the four digits that would shape a genre. Tucked away behind the helipad of UNATCO headquarters on Liberty Island – the scene of Deus Ex’s first terrorist standoff – is a comms van with a satellite dish, made accessible via the famous code. Funnily enough, before joining Ion Storm, lead designer Harvey Smith worked in satellite communications for the US air force. He put together the Liberty Island map, and later worked on both Dishonored and Redfall.

Alumni from Looking Glass and Ion Storm are divided on whether the code references Fahrenheit 451, the 1953 dystopian novel about an American bookburner in a censorious society. But the connection suits Deus Ex, which has a powerful political bent.

BioShock

The code for a new generation.

Given BioShock’s close association with System Shock via Irrational Games, it’s no surprise that 0451 should crop up multiple times over the course of the series. The smartest take on the formula can be found in the overlooked BioShock 2, where the code appears in the fogged-up window of a locked sauna, as if somebody had pressed their finger against the glass pane in a desperate plea for escape.

Since the message is daubed on the opposite side of the glass, it needs reversing to the correct combination, 1540, before it can be used to open up the sauna. Sure enough, there’s a dead body inside – belonging to a Rapture resident who got on the wrong side of her husband by slipping Brain Boost into his breakfast.

Dishonored: Death of the Outsider

Slightly more obtuse.

Arkane is widely recognised as the torch holder for Looking Glass values in the triple-A sphere, and that reputation is reflected in its long history of System Shock easter eggs. In Dishonored 2, 451 is scribbled on a wooden frame behind a painting that can be pulled from the wall of a private residence. And in Death of the Outsider, the code to a safe is hidden in plain sight. “Tally the books over your desk,” one gangster tells another. “Maybe they’ll uncover your memory.”

The shelf above the desk in question carries 10 books in total, split into three piles. No prizes for guessing, at this point, how they’re arranged. It’s a classic Arkane moment – in that it pushes you to really look at the world around you, rather than treating it as set dressing.

Deathloop

Very self-aware.

This roguelike FPS was an experimental break from form for Arkane, and so it’s only fitting that it should break from easter egg tradition, too. As you approach a locked door in the tunnels beneath Deathloop’s party island, Blackreef, you’re taunted by the subconscious of amnesiac protagonist Colt, represented through onscreen text: “You already know the code! This one right here.”

Input 0451, however, and the door will stay resolutely shut. “Old habits die hard,” quips Colt, as a related achievement pops up. At least you’ve unlocked something, eh?

Gloomwood

Shamelessly Thief-ed.

While almost perverse in its commitment to recreating the vibe and aesthetic of Thief – the classic Looking Glass stealth game – Gloomwood nonetheless has a distinct character of its own. As such, when you enter a combination of 451 into any safe in its world, the lock explodes in your face. Take that, tradition.

Watch on YouTube

In a further twist, and to the delight of developer Dillon Rogers, some Gloomwood players have begun to exploit that explosive potential – laying traps for enemies and setting off the bomb deliberately to cause massive damage. Now that’s the Looking Glass spirit.

Atomic Heart

Watch on YouTube

Mundfish’s FPS is at least thrice removed from System Shock on the Looking Glass family tree – pulling more from the shoot-first spectacle of Bioshock Infinite than any true immersive sim. Nonetheless, it pays tribute to its forefathers during what’s best described as a theme park tugboat ride. As you glide serenely past a pair of NPCs, one passes the four-digit control code for a group of malfunctioning robots to their fellow, so that some nearby houses can get painted.

Looking Glass wouldn’t approve of the rollercoaster-esque absence of interactivity, but the pig on a leash is undeniably a new and surprising addition to this old ritual.

Redfall

Keep your eyes peeled.

Arkane’s new co-op shooter, Redfall, strays further from Looking Glass and its ideals than any other game in the studio’s softography. It’s appropriate, then, that its nods to System Shock are subtle and easily missed. First (at the 23 second mark of its launch trailer, above) there’s a penciled note about a 04:51am rally at the fire station which doubles as Redfall’s hub. And second, there’s a parked police car in the game bearing ‘RF04510’ as its registration. You’ll find other references to the number in notes scattered around Redfall’s open world.

BONUS: Slayer Shock

Eerily, there’s a very similar car registration plate in Slayer Shock – the indie immersive sim from Minor Key Games that launched in 2016 and, yes, tasked you with saving a town from encroaching vampires. Slayer Shock’s developer has catalogued these coincidences on Twitter, in a thread cheekily dubbed ‘I am owed royalties for Redfall’.


If only Looking Glass were still around to pick up its own royalties. Still: it’s encouraging to think that developers today continue to seek association with the studio and its ideas. And even more encouraging to see a new generation take those ideas and subvert them - blowing up the conventions of immersive sims as a mark of respect to a studio of forward-thinkers.

Read this next