How to describe a game so the AI builds what you want
Say what the player does, how they control it on a keyboard and on a phone, how they win and lose, and how it should look. Two to five specific sentences beat a long vague one.
On Go Bananas, your description is the design document. The AI turns it into a playable game in a few minutes, so every detail you leave out is a decision the AI makes for you. This guide shows what to include, gives a template and examples, and explains how to ask for changes once the game exists.
What to include
A strong description answers these questions:
- Genre: platformer, top-down shooter, racing, puzzle, match-3, tower defense, card game, quiz, board game.
- The player's goal: what they're trying to do, in one sentence.
- Controls: keys on a computer and taps or swipes on a phone. Games on Go Bananas are played on both, so say how each should work.
- Winning and losing: what ends the game, or whether it's endless with a high score.
- Enemies, obstacles and levels: what gets in the way, and how it gets harder.
- Visual style: pixel art, neon, hand-drawn, cartoon, minimal, realistic 3D.
- Sound: sound effects, background music, or none.
- Multiplayer: solo, or with friends, and whether they play at the same time or take turns.
- Length: a two-minute arcade round, or several levels.
You don't need all of them every time. The more of them you answer, the closer the first version will be to what you pictured.
A template you can copy
A [genre] game where [the player's goal].
Controls: [keys] on a computer; [taps/swipes/buttons] on a phone.
You win when [condition]. You lose when [condition].
[Enemies, obstacles or levels, and how difficulty rises.]
Style: [visual style]. Sound: [what you want].
[Solo, or multiplayer for N players, at the same time or taking turns.]Examples that work, and why
An arcade game
A top-down space shooter where you defend a planet from waves of asteroids. Arrow keys to move and space to fire; on phones, drag to move and the ship fires automatically. Each wave has more asteroids, and every fifth wave has a big asteroid that splits in two. Three lives. Neon synthwave colors, explosion sounds, and a high score on the game over screen.
Why it works: the goal, controls on both devices, the difficulty rise, lives, style and sound are all there.
A platformer
A side-scrolling platformer where a fox collects 20 acorns to open the gate at the end of the level. Arrow keys to run, space to jump, double jump allowed; on phones, left and right buttons and a jump button. Hedgehogs walk back and forth and cost you a life if you touch them. Three lives. Bright cartoon style.
Why it works: one clear goal with a number, a specific ability (double jump), one enemy type with a rule, and phone buttons named.
A puzzle game
A match-3 puzzle on an 8 by 8 grid of fruit. Swap two neighboring fruits to make a line of three or more; matches disappear and new fruit falls from the top. You have 30 moves to reach 5,000 points. Combos of 4 or more score double. Soft pastel colors and a pop sound for each match.
Why it works: grid size, the swap rule, the move limit and the scoring rule leave little to guess.
A two-player game
A two-player tank battle in a maze with walls that break after three hits. Players take turns online; on your turn you aim with the mouse or by dragging, and fire with a click or tap. First to 5 hits wins. Top-down, retro pixel art.
Why it works: it says multiplayer, turn-based, and how aiming works on both devices.
A quiz
A trivia quiz about the solar system with 15 multiple-choice questions, four answers each, and a 15-second timer per question. Correct answers give 100 points plus a bonus for speed. Show the right answer after each question and a final score at the end. Clean, colorful style with big buttons for phones.
Why it works: number of questions, format, timer and scoring are all specified.
Weak and strong descriptions
| Weak | Stronger |
|---|---|
| A racing game | A top-down racing game on a snowy track against three computer cars; arrow keys or tilt buttons on phones; three laps; first to finish wins |
| A scary game | A first-person game in a dark house where you find three keys with a flashlight before a ghost catches you; WASD and mouse, joystick and drag on phones |
| Make it fun | Add a combo counter: each enemy hit within 2 seconds of the last one doubles the points, up to 8x |
| A game like Tetris | A falling-blocks puzzle on a 10 by 20 grid; full rows clear and score 100 points; blocks fall faster every 10 rows |
The weak versions aren't wrong, but they leave every decision to the AI. Asking for "a game like" a famous game also works less well than describing the rules you want, and the result is your own game rather than a copy.
Using your own pictures, sounds and models
If you've uploaded files to Go Bananas, you can ask the AI to use them. Type @ in the create box or the edit box and pick a file: its name goes into your description in quotes. For example:
Use "knight" as the player character and "castle-music" as the background music.
The name is the file's name without its extension. Each file type has its own page with limits and tips: see all supported file formats.
Long design documents
The create box takes up to 30,000 characters. If you've written a full design elsewhere (for example, worked out with ChatGPT), you can paste the whole thing. Long designs work best when they're organized: goal, controls, rules, levels, style. Keep in mind that the AI aims for a game that fits in one go; a finished small game always beats an unfinished big one. If a game is cut off because it was too big, you aren't charged, and the fix is to simplify the description or build it in stages.
Asking for changes afterwards
Once the game exists, you change it by describing the change in the editor. The AI edits your game's code directly, so precise requests work best:
- Name the element: "the score in the top-right corner", "the red enemies", "the start button".
- Use numbers: "change the player speed from 5 to 8", "make the timer 90 seconds instead of 60".
- Say where: "move the lives counter to the top-left".
- One change at a time: it's easier to see what each change did, and easier to undo one from the Versions tab.
Edits usually take under a minute. If the AI's change can't be applied to your game, nothing changes and you aren't charged (up to 10 times a day). If a request is too big for an edit, the AI can rebuild the game from a fresh description instead.
Good change requests:
- "Add a pause button in the top-right corner that also works with the P key."
- "Make the jump 20% higher and the fall slower."
- "On Easy, give the player 5 lives instead of 3."
- "Add a coin sound when the player collects a coin."
What the AI won't make
The AI makes games. If a request isn't for a game, such as an essay or a website, it says so and you aren't charged. If it refuses a request, it asks you to rephrase, and that isn't charged either.