Doom (1993): The Level Design That Still Teaches

I had an Amiga in December 1993, which meant I met Doom the way most people I knew met it: crowded round somebody’s 486 in a bedroom, watching a shareware copy that had come off a bulletin board via three intermediaries. The machine I owned could not do this. That was the first thing anyone understood about Doom — the sense that a line had been crossed and your hardware was on the wrong side of it.

Thirty years later the technology is a museum piece and the levels are still being studied. That’s the interesting inversion. Carmack’s renderer was the news in 1993 and it was obsolete inside three years. Romero’s episode one is still, as far as I’m concerned, the most efficient short course in spatial design the medium has produced, and you can finish it in ninety minutes.

What the engine could not do

Start with the constraints, because the design is a response to them and it reads as nonsense otherwise.

The Doom engine is not 3D. It’s a two-dimensional map with height information — sectors with a floor and a ceiling, walls that are always vertical, and a strict prohibition on one room existing above another. You cannot look up or down; the game auto-aims vertically for you. You cannot jump. There are no genuine stairs, only floors at increasing heights that you walk onto. Enemies are flat billboards that turn to face you.

Now notice what falls out of that. Because rooms cannot stack, every map is a floorplan — a thing you can read from above, which is exactly what the automap gives you. Because you can’t look up, verticality has to be communicated through lighting and floor height rather than sightlines. Because you can’t jump, every route is walkable, which means the designer controls the graph absolutely.

A lesser team treats that list as a set of apologies. id treated it as a grammar. The maps in Doom are legible in a way that later, genuinely-3D shooters lost, and the legibility is downstream of the engine’s limits. When Quake arrived three years later with real 3D, it gained rooms over rooms and lost the floorplan, and level design spent a decade getting worse before it worked out how to compensate.

The keycard is a teaching device

The core loop is a lock and a key. Find the blue door, find the blue card, come back. It’s so foundational that it’s now a punchline about lazy design, which is unfair to what it’s doing in E1.

The keycard is a forced re-traversal machine. It sends you back through space you’ve already cleared, which does three separate jobs at once. It doubles the value of every room built, which matters enormously when your art budget is a handful of textures. It lets the designer re-populate a known space with new monsters and turn a safe corridor into an ambush, so the map has a memory. And it teaches the geography, because you can’t learn a place by walking through it once.

Romero’s craft is in how the returns are shaped. The way back is almost never the way you came — there’s a shortcut door that opens from the far side, a lift you can now call, a window you were shot through an hour ago that turns out to be a route. Every one of those is a small revelation about a place you thought you’d finished with, and it’s the mechanism Dark Souls would later make its whole reputation on at a much larger scale. The shortcut that folds a level back on itself is a Doom idea. FromSoftware just made you feel it for forty hours instead of five minutes.

Contrast, and the reason you never get lost

Romero has published his level-design rules over the years and they’re worth reading, though you can reverse-engineer most of them from playing E1 attentively. The one that matters most is contrast.

Change the floor height when you change the texture. Put a bright room next to a dark one. Follow a tight corridor with a hall. Make the outdoor areas actually feel outdoor by dropping the ceiling light to full and the walls to a different palette. None of this is decoration — it’s the navigation system. There is no quest marker in Doom, no compass, no objective text, and you never get lost, because every space in the map is different from its neighbours and your brain is doing landmark navigation without being asked.

That’s a design lineage that runs straight into the tutorial and the art of not explaining, and it’s genuinely instructive to compare it to the modern alternative. The reason a 2020s open world needs a marker on your compass is that its spaces are procedurally similar. Homogenise the environment and you must add a HUD to compensate. Romero’s maps don’t need a HUD because no two rooms look alike.

E1M1 does the whole syllabus in four minutes. A green-lit start room, a window showing you a place you’ll get to later, a zigzag corridor teaching you that enemies come from angles, a nukage pit teaching you that the floor can hurt you, a secret teaching you that walls are worth pushing. There’s no text. You learn all of it by being in it.

The monsters are a rock-paper-scissors set

The other half of the design is the roster, and it’s tighter than it gets credit for.

Former humans and sergeants are hitscan: they hit you the instant they fire, so the answer is cover and killing them first. Imps throw a fireball that travels, so the answer is movement — you can literally sidestep it, and the game teaches you this by giving you an imp in an open room. Pinkies are melee only, so they’re a spatial threat: dangerous in a corridor, trivial in a hall. Cacodemons float and change the vertical read. Barons soak damage and are placed to be a duration problem rather than a reflex one.

Put those in a room together and you get a genuine tactical read, and then id added the thing that makes it sing: infighting. Monsters that take damage from each other retaliate against each other. That single rule converts a crowd from an obstacle into a system you can manipulate. Get the baron to eat an imp’s fireball and step back. Nothing in the game tells you this exists. Everyone discovers it, everyone remembers discovering it, and it’s the ancestor of every combat arena that asks you to use the enemies against each other — including Doom Eternal’s explicit reworking of the shooter as a puzzle, which took the arena logic and made it mandatory.

The weapon set has no filler

Eight weapons, and the remarkable thing is that none of them is obsolete by the end. That’s rare. The standard shooter arms you in ascending order and the pistol is scenery by level three.

Doom avoids it through ammo. The chaingun and the shotgun draw from different pools, the rocket launcher and the plasma gun from two more, and none of the pools is generous enough to live in. So the question in any given room isn’t which gun is best. It’s which gun you can afford to spend here, given what’s coming. That’s an economy doing the work a weapon-tier list would otherwise do, and it keeps the shotgun — a slow, close-range, gloriously loud thing — relevant for the entire game because its shells are the ones you always have.

The chainsaw is the outlier and it’s the sharpest bit of tuning in the set. It’s a downgrade in every measurable way and it’s free forever, which makes it a genuine decision: walk into a pinky’s face with no ammo cost, or spend shells you might want later. A weapon that’s bad on purpose, priced correctly, and therefore never dead.

Where to play it

Doom runs on everything. The joke has been running so long it’s stopped being a joke. The sensible route today is a source port — GZDoom or Chocolate Doom depending on whether you want quality-of-life or historical accuracy — and the original WADs, which have been sold and resold in every storefront that has ever existed.

Play E1 with the automap key bound and look at it after each level. The floorplan is the text. And when you’re done, the reason there’s fifty thousand community maps sitting on the internet is the shareware model and how Doom spread — id shipped the level format open, and that decision is why this game has never had a year off.

Spoilers below

Doom’s story is nine lines of text between episodes and a marine who never speaks, so there’s little to spoil in the usual sense. The endings are worth talking about as design, though.

E1M8, Phobos Anomaly, is the first boss and it’s a trick. You clear a starburst-shaped room and two Barons of Hell drop in — the Bruiser Brothers — and they are, mechanically, just very large imps with more health. The fight is a lesson in space management: circle-strafe, use the pillars, let them infight if you can bait it. Then you win, and the game kills you anyway. Non-negotiably. The floor opens and you go to hell, which is the shareware episode’s cliffhanger and one of the great sales pitches in the medium’s history — you have just been told that the free part is over and the story continues in the box you have to buy.

E2M8 gives you the Cyberdemon in a bare stone room with nothing but pillars, which is the purest encounter id ever built: one enemy, no scenery, rockets that will kill you in two hits, and the only answer is movement. E3M8 hands you the Spider Mastermind and a hitscan chaingun that shreds you across the whole arena, and the correct solution is the BFG at close range, which the level quietly makes available.

And then the ending. You kill the Spider Mastermind, the game tells you you’ve won, and the final screen shows your pet rabbit Daisy’s severed head on a spike against a burning skyline. That’s it. That’s the reward for finishing. It’s tossed off, tonally deranged, entirely unearned by anything preceding it, and completely in keeping with a game whose plot was famously considered about as important as a plot in a pornographic film.

The thing that lasted was never the demons. It was a floorplan you could read at a glance, an enemy set where every unit asks a different question, and a designer who understood that a locked door is the cheapest way ever invented to make a player learn a building.