That is very cool! Just spent a bit of time playing with it, and while I wouldn't say I was a 303/808 connoisseur (unlike a friend who is pretty famous for his use of them), sounds pretty good to me; it's not perfect (it sounds like the filters aren't quite there in terms of extreme settings of resonance and envelope), but it's good. I've not used RB338 for years, so it could be mis-remembering, but it's almost like the sounds need controls that 'go to 11' to get to where you'd want them to be?

I like the simplicity of it and the ease of producing a WAV from a session, and the UI seems to be simple and straightforward to use. I'll test it out on some students this week, see what they come up with.

I have a couple of minor criticisms - I don't think the ballistics of the rotary controls is right, but I can't quite put my finger on -why-, just seems a bit too sensitive or there's something about the linearity of it? Would it be possible to add the Cubase-style "shift reduces the sensitivity while dragging" to them?

The other thing was editing the grid - I'd prefer left click to toggle an event on and off rather than right-click to clear; while this is personal preference, it's one that I've got used to using Cubase for 20 years or so in the drum editor, so it's a little counter-intuitive to have to do it another way, and I think many other editors are similar?

Finally, any chance of an undo in the editor?

But overall, love it. An amazing demonstration of what's possible in a browser, and of your skills!