Hi there!
This is an NES emulator written in Rust completely from scratch purely based on publicly available documentation.
What you see here is its port compiled to WebAssembly using the magic of the stdweb crate and Rust's native WebAssembly backend, without the use of Emscripten.
You can take a peek at the code if you're interested, but first I invite you to take it for a spin and play a few games!
You can chose between a few fun freeware NES games, but if you have the ROMs then games like Super Mario Brothers, Contra, Legend of Zelda, or Final Fantasy will work too!
Controls are Z and X for A and B, Enter and Right Shift for Start and Select, and the arrow keys!
You might also want to check out the version compiled *with* Emscripten to WebAssembly or to asm.js.
Maybe try something newer which supports WebAssembly?
The error message is as follows:
Sorry about that! Maybe try another ROM?