Risk of Rain 2: The Difficulty Curve as a Clock

Most games measure difficulty against you. You get better, so they get harder; you fail, so they ease off. Risk of Rain 2 measures difficulty against the clock on the wall, and the clock does not care whether you are ready.

There is a readout in the top-right corner. It tells you how long you have been alive and it tells you, in a word, how much trouble you are in. It starts at Easy. Given long enough it stops using words that mean anything and starts shouting at you. Nothing you do slows it down. You can stand perfectly still in an empty corner of the first map and the number keeps climbing, the enemies keep getting more numerous and more expensive to kill, and the run you were carefully building gets taken away from you by arithmetic.

That single decision — difficulty as a function of elapsed time rather than progress — is what makes this game work, and it’s why it has outlasted a good many slicker things released since.

What it actually is

Hopoo Games released Risk of Rain 2 into Early Access in March 2019 and hit 1.0 in August 2020, on PC and every current console. It is the 3D sequel to Risk of Rain (2013), a 2D side-scroller with the same architecture and a much meaner silhouette. Gearbox published both and later bought the property outright.

The loop is simple enough to explain in a lift. You drop onto a stage as one of a roster of survivors — Commando, Huntress, Engineer, MUL-T and a dozen others, each unlocked by a specific challenge. You kill things, which drops gold. You spend gold on chests, which drop items. Items are permanent for the run and they stack: two of a thing is roughly twice the thing, six of a thing is a problem for whatever is standing in front of you. Somewhere on the map is a teleporter. You activate it, survive the boss and the charge window, and move to the next stage. After five stages you loop back to the beginning with everything harder and everything you own still in your pocket.

Items are the whole texture. A white common item that gives a small chance of chaining lightning is a shrug at one stack and a screen-clearing weather system at twelve. The red-tier legendaries change the rules rather than the numbers — one of them, famously, lets you cheat death once per stage, and the run in which you find it becomes a different run. Lunar items are the interesting ones: they come with an explicit cost, a real downside written on the tin, and picking one up is the game asking whether you understand your own build well enough to pay.

The clock is the design

Here is the thing everything else hangs from. Gold scales with time. Chest prices scale with time. Enemy health and damage scale with time. So the more chests you open, the stronger you are — and the longer you spent opening them, the stronger everything else is.

That’s not a difficulty setting. It’s an economy with an interest rate.

Every decision in a run is the same decision wearing a different hat. There’s a chest on a ledge across the map. Getting there costs ninety seconds. Ninety seconds is worth a certain amount of enemy scaling, and the item in the chest is worth an unknown amount of power, and you have to price that trade with incomplete information while a horde is assembling behind you. Do it right and you leave the stage marginally ahead. Do it four times in a row on a stage where the chests roll badly and you leave the stage behind the curve, and being behind the curve compounds, because a weaker character kills more slowly, and killing more slowly takes more time, and time is the thing that is hurting you.

The genius is that the punishment for greed is never immediate. Spelunky’s ghost arrives at two minutes thirty and tells you off in person. Risk of Rain 2 lets you overstay, gives you the loot, sends you happily to the next stage, and then kills you eleven minutes later with a bill you signed without reading. You almost never die of the mistake you just made. You die of the mistake you made two stages ago, and by the time you understand that, you’ve internalised the pacing in a way no tutorial could have taught you.

Compare the timed doors in Dead Cells, which do something adjacent and much more legible: run fast, get a reward, and the reward is gone the instant the timer expires. That’s a clean, honest bargain you can evaluate in a second. Risk of Rain 2’s bargain is smeared across an hour and you’re never quite sure you got it right. The uncertainty is the product.

Why the power fantasy lands

Roguelikes have a structural problem with escalation. If the player gets strong enough to trivialise the content, the game stops being interesting; so most designs cap the player, or scale the enemies to match, or reset the whole apparatus every run. Hopoo went the other way and let the ceiling off entirely.

By the third loop a well-built survivor is a war crime. The screen is a smear of proc effects, ricochets, mortars, satellite lasers and burning ground, and you are killing bosses in the time it takes them to finish their spawn animation. This is the same joy that Vampire Survivors later refined into a pure distillate — the pleasure of watching your own build outgrow your ability to follow what it’s doing.

The difference is that Risk of Rain 2 charges for it. Vampire Survivors ends at thirty minutes and hands you the victory lap. Risk of Rain 2’s clock keeps ticking past the point where your build is godlike, and the scaling curve is exponential where your item stacking is roughly linear. So the god phase is a phase. It has a shelf life. You are always, at every moment of the run, watching two lines on an invisible graph and trying to guess where they cross — and the right play is often to leave a stage with money in your pocket and chests unopened, which feels physically wrong and is correct.

Very few games make walking away from free loot into a skill.

Where it fights itself

The 3D translation cost something real. The 2013 original was a side-scroller, and a side-scroller tells you where everything is. In three dimensions, with a camera behind your shoulder and enemies spawning off-screen in every direction, the fair-fight legibility goes. Late in a run you will be killed by something you never saw, from a direction you had no reason to check, and the game’s answer to that is a minimap you don’t have and a sound mix that is already saturated. The tension between “readable combat” and “the screen should be chaos” never quite resolves.

The other cost is the ramp-in. The first ten minutes of a run are, by design, the least interesting ten minutes. Difficulty is low, items are few, and you are essentially doing paperwork to build a character. Once you’ve had four hundred runs, those minutes are a chore you tolerate. The scaling clock justifies it — you cannot skip the early game without also skipping the item economy — and I still think it’s the strongest argument for the design and the most obvious tax on your evening.

Multiplayer is where the seams show most. Up to four players share a stage, item drops don’t scale cleanly, and the difficulty coefficient rises with player count in a way that makes an uncoordinated four-stack a farm and a coordinated one a rout. It’s a joy to play with friends and it is not a balanced experience, and Hopoo were fairly upfront that it was never going to be.

The ancestor

Everyone reaches for Isaac or Spelunky here, and the resemblance is surface. The real ancestor of Risk of Rain 2 is the arcade timer — the coin-op design where the machine’s job is to end your session on a schedule, whatever your skill, and skill only buys you a longer schedule. Every one of those cabinets had a hidden rank system pushing back against a player who got too good.

The trick Hopoo pulled is exposing that clock, putting it in the corner of the screen, and making it the thing you play against rather than the thing that plays against you. Hades solved repetition by making the loop mean something narratively. Risk of Rain 2 solved it by making the loop mean something economically. Both are answers to the same question: why should I press start again? Hopoo’s answer is that last time you left two chests behind and you’ve spent the intervening hour wondering whether you should have.

The verdict

Risk of Rain 2 is the most honest tension engine in the genre. It gives you one number, tells you the number is your enemy, hands you every tool you need to manage it, and then quietly makes managing it the entire game. The combat is loose, the camera is a liability, the early minutes drag, the multiplayer is lopsided — and none of that matters much, because the thing it does is something almost nothing else does, and it does it for as long as you keep asking.

Play it on PC, where the mod scene has been carrying it for years and where the frame rate survives what the third loop does to the entity count. The console versions are complete and competent; they just wilt at the top end, which is where the game is.

Then, if the loop takes, go and see what Vampire Survivors does when you remove the ceiling and the aiming. It’s the same drug with the difficulty clock swapped for a shorter fuse.

Spoilers below

The reason the loop mechanic works — going back to Stage 1 with a difficulty coefficient that has never reset — is that it makes the map geography a memory test rather than a discovery. You already know where the chests are on Titanic Plains. You know where the shrine spawns cluster. So the second loop asks you to run a route you know at a speed you can’t quite sustain, and the pleasure flips from exploration to execution without changing a single asset.

The obliteration ending is the part I keep thinking about. You can end a run voluntarily, at the obelisk, by choosing to erase yourself. It’s the only exit that isn’t death and it costs you the run’s rewards. A game built entirely on the tension between greed and the clock offers you, as its cleanest ending, the option to stop wanting things. That’s a better joke than it has any right to be, and it took me a long time to notice it was a joke about me.