Vibe coding a game, one playable change at a time

Vibe coding a game means you describe a change to an AI, play the result and decide what needs fixing. The name comes from Andrej Karpathy, who described a style where you “fully give in to the vibes” (the post). Later, Collins named it its Word of the Year for 2025 (Collins).

Vibe Jam went as far as making it an entry rule, so most of the code had to come from AI. That still leaves you plenty of decisions, like choosing the loop, trying the controls and deciding when a build is ready.

Play after every change

Working in small loops keeps a game playable while it grows. To give you a sense of scale, Kanso was built with Codex in about a week of a month-long jam, according to its creator. It’s a bonsai game, and it placed ninth and won the jam’s Most Zen award.

1. Describe one loop in one sentence. Our catalog’s taglines are a handy guide to the scale. Fanto’s Mega-Mart, second at Vibe Jam 2026, is a race “through a haunted grocery store at rocket speed, grabbing items as you go.”

2. Ask for the smallest playable slice. That’s movement, one hazard and a score, and nothing else yet. Run it before you ask for more.

3. Play after every change, then report what you saw. Claude Code’s docs advise giving the agent the symptom, the likely location and what “fixed” looks like (best practices).

4. Write the standing rules down once. The engine, the run command and “play a round after every change” go in CLAUDE.md or AGENTS.md, which the agent reads every session, so you don’t have to repeat them. 10 prompts to copy has a four-line example.

5. Commit every version that plays. git add -A && git commit -m "wave spawner works" takes seconds and is basically free insurance, and git restore . throws away uncommitted edits to tracked files when an attempt goes wrong. Claude Code’s checkpoints aren’t a replacement for git, according to its docs.

6. Restart when the session gets messy. After two failed corrections, the same docs advise clearing the session (/clear in Claude Code) and writing a sharper prompt.

7. Polish last, one effect at a time. Once the loop is fun, screen shake, a hit sound and a death animation each get their own message. Game feel with AI has the numbers to start from.

Name the symptom and what fixed looks like

A specific prompt names a symptom, a place and what fixed looks like. The pattern comes from Claude Code’s docs, and the examples are ours.

Vague	Specific
Make the game more fun.	Enemies spawn every 10 seconds. Add a wave counter and add two enemies to each new wave.
Fix the controls.	On a phone, dragging the left half of the screen moves the ship and tapping the right half fires. Right now dragging scrolls the page.
It runs slowly.	On my phone the frame rate drops to about 20 when 50 enemies are on screen. Find the cause, fix it and tell me what you changed.

A first prompt in that spirit might look like this.

Build a one-page browser game with Three.js.
The player flies a small ship. Keyboard: arrow keys or WASD to move, Space to fire.
Phone: drag to move, tap to fire.
Enemies drift in from the top; the run ends when one touches the ship.
Show the score, and keep the best score after a reload.
R or a Restart button starts a new run without reloading the page.
The ship moves at the same speed at 30 and at 120 frames per second.
Run it, play one round with the keyboard and tell me what you see.

Then check the result against the prompt yourself. Try both control schemes, make sure a restart clears the score but keeps the best one, and check that the speed is the same on a slow phone as on your desktop. Each miss becomes your next specific prompt.

10 prompts to copy and adapt has a template for each step of a build.

Where vibe coding goes wrong

When it goes wrong, it’s mostly in one of three places, which are code nobody checked, scope that grew too early and rules nobody read.

• Code nobody checked. Claude Code’s docs warn about plausible-looking code that misses edge cases, and tell you not to ship what you can’t verify. Playtesting games with AI turns that advice into a test the agent runs by itself.

• Scope that grew too early. Multiplayer brings a server, netcode and hosting with it. Add it after the single-player loop is fun, and read make a multiplayer game with AI first.

• Rules nobody read. Vibe Jam 2026 required AI-written code, while other jams and stores set their own terms. Selling AI-made games covers Steam and itch.io.

On Steam, the public documentation names art, sound, narrative and localization as the content to disclose (Content Survey). Game Developer reported on January 16, 2026 that code helper tools used for workflow don’t need disclosure (Game Developer).

What did Vibe Jam 2026 require?

It asked for AI-written code, new games and free play on the web (jam rules), and it ran for a month.

Jam window	Date
Start	April 1, 2026
End	May 1, 2026

• AI share. At least 90% of the code had to be written by AI.

• New work. No games that existed before April 1, and one entry per person.

• Access. Each game had to be playable on the web, free, with no login or signup, and load almost instantly, without loading screens or heavy downloads.

• Widget. The jam’s JavaScript snippet had to be in the game, or the entry was disqualified.

• Entries. The jam drew 945 games, according to its press page.

The rule only counts who wrote the code. Karpathy’s post was about forgetting the code even exists, and the jam doesn’t ask anything like that.

Vibe coding game jam compares these rules with what other jams allow.

The same method makes a bonsai garden or ASCII horror

In Kanso you grow a bonsai tree, while HALDANE-4 sends you down beneath the Antarctic ice. Both were made with coding agents, and you can see how little they have in common, from the controls to the art.

The tool credits come from creators, mostly through the jam submission form, and the counts are current as of November 14, 2026. We don’t independently verify those credits (how we count).

Trait	Games (of 588)
Built on Three.js	322 (55%)
List mobile as a platform	293 (50%)
Have online multiplayer	200 (34%)
Name Claude Code	224 (38%)
Name Codex	101 (17%)
Name Cursor	106 (18%)

Action is the most common genre tag, and shooter, simulation and strategy come up regularly too. A game can carry up to three genres, so those overlap, and you can browse each one on the action, shooter, simulation and strategy hubs.

The typical vibe-coded game we list is a real-time scene in a browser, often playable on a phone and often with other players. The jam nudged people that way too, though, since its rules say Three.js is usually recommended and multiplayer games are preferred but not required.

Not every game fits that picture.

HALDANE-4’s ASCII descent lists no engine at all, and it was made with Cursor and won Most Original at the jam. It isn’t the only one, either, since other creators also leave the engine unstated.

Pick a tool and ship it

How to make a game with AI is the place to start for tools and publishing. You can see what each agent produced on the Claude Code, Codex and Cursor hubs, or compare them in best AI game makers. If there’s a jam coming up, read vibe coding game jam.

For more games to look at, there’s the Three.js hub, the Vibe Jam 2026 entries and the top rated games. And once you’ve made one yourself, you can submit your game.