I did share the prompt, it's right below the game :) I do the same for most of the games I build (one each day). Some of the games take a lot of prompts to fix/adjust things, but most require only a single prompt -- this one (Tower Defense) required just 1 sentence, a few words, that's it

As for the language, the whole application is set up with c#/.net on the backend and React/vite/js on the frontend so each game is built with that in mind. No gaming engines or physics libraries or anything, Claude handwrites all of it.