Looks like a big effort. It is interesting that they are trying to port by hand instead of using emscripten.

I used emscripten to port the MOAI engine (lua 2.5d engine) to HTML/JS, and it runs pretty smoothly (needs webGL).

you can see an older version of the player working here: http://moaijs.moaiforge.com/progrocket/index.html

I also created a jsfiddle style interface for it so you can play with it in the browser. http://moaifiddle.com

Oh, wow, that's very cool! How did you deal with the 3rd party dependencies? Is that open-source anywhere? I would love to see what you had to do in order to get that working.

I'm the author of the above-mentioned punchdrunk, by the way. There were three reasons that I decided to do the port by hand: 1) I wanted to preserve mobile support by falling back to 2d-canvas when necessary. 2) I wanted to really cut my teeth on some graphics programming because I'd never really had the chance before. 3) I just couldn't get the damn thing to compile with emscripten (which I why I'd be very interested in your process).

We are considering emscripten for other modules like love.physics: https://github.com/TannerRogalsky/punchdrunk/issues/38

Moai is opensource and the html host has been merged. http://github.com/moai/moai-dev , (moaifiddle is also opensource but doesn't actually build the moaijs.js file (it just uses a prebuilt one. http://github.com/halfnelson/moaifiddle)

Third party dependencies are all statically linked and compiled by emscripten too, so the moaijs.js includes box2d, lua, libpng, libjpg, tinyxml all compiled in from their sources.

Best of luck!