Including some sample mp3s to directly start playing around would be great. I pressed 'q' and nothing happened. :/

You passed the 16th note high hat test! Well done.

FWIW, you said "mp3" but I just used the first folder of one-shot samples I came across, which happened to be WAVs and worked fine, but may have contributed to Chrome crashing when I hit the back button.

As far as royalty free samples go, you might want to take a look at http://freesound.org, or one of my personal favorites, http://hellosamples.com

Requests: Keymappings for rec/stop/play/undo/pitchbend, a fourth row of pads, maybe sample slicing?

Off the top of my head, things that this is lacking: velocity control for each pad, a way to zoom in on waveforms and chop up samples, maybe better loop controls, and the ability to export as .wav?

But suggestions aside, as a budding hip-hop producer/hacker, I had the idea to make this but never the skills/conviction. It made my day to see that this is something actually doable, and capable of being done well.

I get 'unsupported file format' when i try to load an mp3. Chromium 16, tried several mp3s.

Also, the font rendering of the instructions is pretty awful for me -- http://imgur.com/Iy31O

Neat idea though.

Could I get a volume control/equalizer in there? My mp3s seem to be not really normalized.

But its a lot of fun to play with!

Clicking record repeatedly while it's playing back an existing pattern creates some awesome cacophony.

I tried dragging mp3 samples as instructed and nothing happen! Using Chrome on Windows 7.

Pretty nice. Forked!

Is this it for the demo, or do you plan to continue development?

Why should it need Chrome. This is just as bad as needing IE6 twelve years ago.