DIY: make a simple game in a weekend with an AI coding assistant — one mechanic, browser first, your own art and music

You have an idea for a small game — for fun, for your brand, for a channel, for a store listing. The reflex is a game engine with a 40-hour tutorial or a developer at a day rate. This is the line that produced nineteen playable prototypes for my studio, cut down to one game and one weekend.

You end up with

A playable browser game with one mechanic, your own art and sound, running on your phone and shareable as a link — the thing you can then wrap for a store

What it costs

Under €10 all in: assistant subscription or free tier, cents per generated sprite, a track you already made. Web hosting free

How long

A weekend. The first playable version should exist by Saturday lunch

Runs on

An AI coding assistant · a text editor · a browser on your laptop and your phone · an image model for sprites · your track from the music recipe · a free static host

Step 1 — one mechanic, written as a spec

The reason most first games die is scope. Write one paragraph that describes one thing the player does and one way they lose. Not “a platformer with power-ups and levels” — “tap to jump over gaps; the gaps get wider; fall and it’s over; the score is the distance.” If the paragraph needs a second verb, it is two games.

Then add the constraints the assistant needs and won’t guess: portrait or landscape, touch and keyboard, one HTML file, no frameworks, no build step, 60 frames per second on a mid-range phone.

Step 2 — the first build, in plain HTML

Give the assistant the paragraph and ask for a single index.html with a <canvas>, the game loop, touch and keyboard input, a score, a start screen and a game-over screen — placeholder shapes for everything, no art yet. Open it in a browser. Play it. It will be ugly and it will almost work.

Now iterate the only way that works: play, describe precisely, paste the description back. “When I hold the screen the character jumps repeatedly; it should jump once per tap.” One change per message. Save each version with a number.

Step 3 — put it on your phone by Saturday lunch

Run a one-line local web server from the folder (the assistant will give you the command) and open the laptop’s address on your phone over the same Wi-Fi. Every save is a refresh on the phone. Touch feels different from a mouse — the thing that was fun on the laptop may be unplayable with a thumb, and you want to know that on Saturday, not on Sunday night.

Step 4 — art and sound, yours

Replace the placeholder shapes with sprites from an image model: your style sentence from the identity recipe, one subject per prompt, plain background, then cut out. Generate a sprite sheet of variants for anything that animates. Keep it small — a one-verb game needs a hero, an obstacle, a background and a few UI marks.

Music: the loop from the track recipe, plus two or three short sounds (tap, score, lose) generated the same way or recorded on your phone. My studio’s soundtracks came from my own label’s catalog at zero extra cost — that is the kind of cross-project leverage a solo builder gets for free.

Step 5 — the parts a store will ask for later

Not needed to play, cheap to add now, painful to add later:

• English by default, with strings in one place so a second language is a file, not a rewrite.
• A pause and a mute. Reviewers look for them.
• A record mode — a flag in the URL that hides the buttons and runs a clean demo — so the promo video and the store screenshots come from the game itself, not from a mock-up.
• A privacy line and a version number on the start screen.

Step 6 — ship it as a link

Put the folder on a free static host and send the link to five people. Watch them play without explaining anything. Whatever they don’t understand in the first ten seconds is your Monday task. Twelve of my nineteen prototypes exist because the loop from idea to a playable link was measured in hours; the two that reached a store went through this exact list first.

Where it breaks

• Scope. A second verb crept in. Cut it; write it down for game two.
• “It’s buggy.” Not a bug report. Where, when, what you did, what happened instead.
• Fun on the laptop, dead on the phone. Touch targets too small, or the frame rate dropped. Test on the phone from the first hour.
• The freeze. See the timing box above.
• Art that doesn’t match. No style sentence, or the assistant drew its own placeholder art and you kept it.

Related: the game-studio case · vibecoding for solopreneurs · idea to MVP in a weekend · all recipes in Do it yourself.