Cloverag/pixelforge ? reverse-engineered prompt

Build me a browser based pixel art falling sand sandbox where I can paint different materials and watch them burn, flow, grow, explode, and react with each other in real time.

I want it to feel like a playful science toy, with a sandbox mode, a particle playground for flashy effects, a chemistry lab, a math lab, an ASCII garden, and a set of 7 goal based challenges. It should autosave my world, let me share it with a link, and support playing together with friends in the same world. Add fun extras like a sun and moon cycle, shadows, sound effects, and a few special scenes such as fireworks, portals, black holes, and surprises. Make it run smoothly in the browser, with the simulation handled separately so it stays fast, and use a clean colorful pixel art look.

If you need to look up current docs online for any browser APIs, feel free to do that.