This is my entry for the ludum dare 48 hour compo #26, it requires a HTML5 browser and keyboard. I would recommend you use chrome or a browser with the web audio API, as the fallback to standard HTML5 audio seems patchy with some or all sounds being absent in other browsers. However it should be playable in any browser that supports the canvas element.
You can view a couple of posts by me about the entry on this bit of ludum dare website. It was a lot of fun, and I think I may try a few more projects with strictly limited time scales and random themes as practice and a fun challenge.