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Kart Royale
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About the game
Kart Royale is an arcade kart race for one player against seven computer racers. The track is Sunset Bay Circuit, a three-lap coastal course with a village section, hills on the horizon, banked corners and a sea that catches the light of a sun that never quite sets. You choose one of eight racers, each with different speed, acceleration, handling and weight, and then fight for the front of the pack.
The driving is built around drifting. Hold Shift in a corner and the kart slides while sparks come off the wheels, and the longer you hold the slide the higher the boost you get when you let go: three tiers of mini-turbo, each a different colour. Item boxes along the road give you things to use: a turbo can, a triple turbo, floats that fly straight or home in on a rival, a lemon to drop behind you, a mine, a squall that stuns the other racers and a golden power-up. Where you are in the race decides what the boxes give you.
The unusual part is how it is made. The repository says the game was written by Claude Opus 5 from a single prompt and then improved over nine rounds of AI agents that built and criticised the game, and that no art assets exist at all: not a texture, a model, a font or a sound file. The kerb stripes, the crowd, the tyre tread, the sky, the engine note and the music are all produced by code when the page loads, which is why the first start takes a moment and why the file you download is small.
Playing it here
Click Play and wait for the title screen; the first load compiles a lot of graphics code, so give it ten to twenty seconds. Press Enter, choose a racer and press Start Race. The countdown lets you build speed for the start. The game checks how fast your device is and picks a quality level on its own, and it lowers the resolution when frames get slow. It needs a computer or phone with a decent graphics chip, and it is heavy on older machines. Nothing is saved between visits.
Controls
| Input | Action |
|---|---|
| Left / Right or A / D | steer |
| Up or W | accelerate |
| Down or S | brake and reverse |
| Shift | drift (hold in a corner, release to boost) |
| Space, E or Enter | use the item |
| Esc or P | pause |
| gamepad | stick or d-pad steers, right trigger accelerates, left trigger brakes, bumpers drift, X or Y use the item |
| touch (phone) | on-screen stick and buttons; the Controls button on the title screen picks a layout |
Tips
Start drifting early in long corners. A drift that lasts long enough to climb the sparks to a higher tier gives a much bigger boost than a quick flick of the wheel.
Keep the item for the right moment. A turbo is worth the most on a straight; the lemon and the mine work best when dropped right before a corner, where a racer behind you cannot avoid them.
Stay off the grass. The roadside is slow, and the ground texture and tall grass are a good cue to keep the wheels on the asphalt.
FAQ
Is it a copy of another kart game? No. It is an original game in the same genre; the racers, the track and the items are its own, and there is no artwork from anyone else.
Why does it take a while to start? Everything on screen is generated when the page loads, so the browser compiles its graphics programs first. The same work is why the game weighs only about two megabytes.
Does it run on a phone? It has a touch layout, but it is a demanding 3D game; use a recent phone.
Credits and licence
Kart Royale was made by Ryan Campbell, with the Claude Opus 5 AI doing the programming under his direction, and is released under the MIT licence. It is drawn with the three.js library (MIT), with postprocessing (zlib), n8ao (CC0) and simplex-noise (MIT). In this version we added a security policy that blocks any network request outside the page and removed the manifest used to install the game as an app. The licence texts and the source are linked from this page.