Gato Espacial

Ask for it like this

Copy this prompt, paste it into Claude or ChatGPT, and that's it. It's the short version: the minimum for the game to come out playable.

Make me a slingshot launching game for the browser, in the style of the tower-toppling games, with original art.

- I drag back to aim (a dotted trajectory shows) and release to launch. The projectile flies with gravity and bounces.
- Each level has metal, glass and rock blocks that fall and break with physics, and enemies I have to knock down.
- I get 3 tries per level; I win if I knock down every enemy.
- In mid-flight, one tap gives an extra boost, only once per launch.
- 5 levels, a score and 1 to 3 stars per level.
- Screens: title, the game with level/tries/score, level cleared with stars, retry and ending.
- Controls: drag with mouse or finger; on a phone held upright the camera should zoom and follow the projectile.
Technical: a single HTML file with the CSS and JavaScript inside, no libraries and no external images, everything drawn on canvas. It should fill the window and be playable with a finger on a phone and with keyboard or mouse on a computer.

Getting it as an HTML file

A game like this is a single file you open with a double click. These four steps are the same in any AI.

1. 1. Ask for the whole file

   Add this line at the end of your prompt: Give me a single, complete HTML file, nothing cut out, ready to save as index.html and open in the browser. Without it, you often get the code in pieces.

2. 2. Copy all of the code

   In Claude the game shows up on the side, already running, with a button to copy or download it. In ChatGPT, copy the whole code block: it has to start with <!DOCTYPE html> and end with </html>.

3. 3. Save it as index.html

   Paste it into Notepad (Windows) or TextEdit in plain text mode (Mac) and save it as index.html. Watch out for .txt: if the file ends up as index.html.txt, it won't open as a page.

4. 4. Double-click to open it

   It opens in your browser and it's ready to play, with nothing to install and no internet needed. To share it, upload it to any web host or send it by email: it's just one file.

If the game shows up blank, go back to the AI and paste the error from the browser console (right click → Inspect → Console). With that text it fixes it fast.

The full prompt, the one actually used

Longer and more specific: numbers, screens and style details. It's the one that produced exactly this game, unedited. Use it if you want to fine-tune the result.

Diego wrote it in Spanish and it stays in Spanish on purpose: it's the honest record of how the game was made, and a translation would be a prompt nobody used. Claude and ChatGPT understand it as is; add "Answer in English" if you want the game's text in English.

Hazme un juego de navegador llamado "Jebe Espacial".

La idea: un cohete pequeño se lanza con una resortera (un jebe) hacia estructuras flotando en el espacio, al estilo de los juegos de lanzar pájaros contra torres, pero todo con arte original: nada de pájaros ni cerdos.

Mecánica:
- Arrastras el cohete hacia atrás desde la resortera y lo sueltas. Mientras arrastras se ve la trayectoria punteada.
- El cohete vuela con física: gravedad, rebote y rotación.
- Cada nivel tiene bloques (metal, vidrio, roca) que se caen y se rompen con física real, y "aliens" verdes que hay que tumbar.
- Tienes 3 cohetes por nivel. Ganas si tumbas a todos los aliens.
- Mientras el cohete vuela, un toque o la barra espaciadora activa el propulsor una sola vez: un empujón en la dirección en que apunta.
- 5 niveles que se ponen más difíciles. Puntaje por bloque roto, alien tumbado y cohete sobrante, y de 1 a 3 estrellas por nivel.

Pantallas: título con botón Jugar, el juego con un HUD (nivel, cohetes, puntaje), una pantalla de nivel superado con estrellas, una de reintentar, y el final.

Controles: mouse y pantalla táctil para arrastrar; R para reiniciar el nivel.

Estilo: espacio oscuro con estrellas en parallax, cohete rojo, aliens verdes simpáticos, partículas al chocar y romper, y una sacudida de cámara leve en los impactos fuertes.

Técnico:
- Un solo archivo HTML con todo el CSS y el JavaScript dentro. Sin librerías, sin CDN, sin imágenes externas: todo dibujado en canvas.
- Tiene que llenar la ventana y adaptarse a cualquier tamaño, de celular a pantalla grande, sin deformarse.
- Tiene que funcionar dentro de un iframe con sandbox="allow-scripts". Si guardas el récord, usa localStorage dentro de try/catch para que el juego no se rompa si no hay acceso.
- Se pausa solo cuando la pestaña no está visible.
- El texto del juego va en español.

For ChatGPT, add the line from step 1 at the end: it tends to hand over the code in pieces.

What this prompt was missing

What became clear once the game was finished. If you're making your own from this one, add these from the start: fixing things later costs another round.

• Ask from the start for it to be playable on a phone held upright, with zoom and a camera that follows the rocket. Asking later cost a second round.
• Set how hard the last level should be (for example: winnable with 2 of 3 stars), or it comes out harder than you wanted.
• Ask for sound: if you don't mention it, the game comes out silent.

What was asked after the first result, in Diego's own words (Spanish):

• Hazlo cómodo en celular vertical: que la cámara haga zoom a la resortera, siga al cohete y muestre antes la estructura, sin pedirme girar el teléfono.
• Agrégale un menú de pausa, un botón para cambiar entre español e inglés, y que el récord no se pierda al recargar.
• Cambia el tema a gatos: que el cohete sea un gato astronauta en cápsula y los aliens, perros espaciales, sin tocar la mecánica ni la dificultad.

It works in any AI

Claude, ChatGPT, Gemini, Copilot: the prompt is the same and so is the method. What changes is where you see the result. Four things that hold in all of them:

1. Ask for a single file

   "A single HTML file with everything inside, no libraries or CDN." That way the game works with a double click, with nothing to install, and you can upload it to any website.

2. Ask it to tell you what it assumed

   End with: "before writing the code, tell me in 5 lines what you assumed". That's where the gaps in your prompt show up, while fixing them is still cheap.

3. One fix per message

   Say what happens and what you expected. If you ask for three changes at once, one usually undoes another.

4. Ask it to test, not to promise

   "Check that every level can be won and tell me how you checked." That's how the games on this page found their bugs before going live.

The 6 parts of a good prompt, with a template to copy