Peruvian Myths

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.

ahora peudes hace run juego de cartas como si fuera yu gi oh o magic con reglas simples por turnos tambien multijugador online? ese si lo peudes hacer dentro de mi lista de jeugos

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.

• Naming famous games as a reference works for the mechanics, but you have to explicitly ask for original art, names and cards: otherwise copying is the easy way out.
• Ask for the balance to be SIMULATED and reported: with the classic rule (the first player doesn't draw on their first turn) whoever started won only 41% of the time. Letting them draw and raising life points to 8000 brought it to 53%.
• State the theme and the kind of rules from the start (here, Peruvian legends and a classic duel): they came in later messages and forced the game to be rebuilt twice.

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

• y el juego de cartas que sea algo relacionado tmabien a peru y leyendas peruanas .. que asi se llame el juego algo como mitos peruanos oalgo asi que parezca medio del faraon de yu gi oh o god of war
• que le juego de cartas sea mas como yu gi oh el clasico sin energias que sean con fusiones cartas de ataque y poner en defensa boca abajo boca arriba con cartas trampas y paginacas como el old yu gi oh
• el jeugo de cartas verifica bien creo que no se pued einvocar mosntruos cuando una carta esta en defensa .. que dig ano se puede sacrificar para invocar .. ademas las cartas no te dicen cuantos tirbutos se necesitan .. otra cosa que necesito es que puede estar en ataque o defensa pero indiferentemente si esta boca arriba o boca abajo .. las dos opciones deben estar ahi .. ademas si estan boca abajo yo tmabien las debo ver boca abajo pero cuando paso el cursos o cuando apreto encima me sale un pop o algo que me diga que carta es y su descripcion y lo que hace .. tiene que ser descriptivo como apra que uclauqiera enteinda ..

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