I'm a big believer that interfaces without labels are antagonistic to users, and require you to know how it works in advance. This can be somewhat mitigated by

I'm a big believer that interfaces without labels are antagonistic to users, and require you to know how it works in advance. This can be somewhat mitigated by popping up an instruction box when the user loads the site, but this doesn't do that either, nor does it have a clearly marked 'what the heck' button. I have three sequencers (more if pocket operators count although they only sequence themselves) within arms length of me at the moment, plus a few different software sequencers I use in my DAW, so I guess I'm just a little more picky.