Concept interesting but a little frustrating for me : some times the draw doesn't happen.
Viewing post in BBBBBB jam comments
I retried it today, on Firefox and Chromium it works perfectly and is smooth.
I think I have some process which was running giving less CPU to run this game, I was around ~20-30 fps and in this case it seems your event system handling for the mouse click can miss some. My tip to avoid that is to use the state MouseDown instead of the events MousePress and MouseRelease.