Couldn’t this application theoretically support MIDI input? I haven’t looked to see if it does, but if it does; velocity is a simple enough feature to implement with even just a simple volume curve.
Not just yet, MIDI input is the next big feature I want to add! =)
("dang it!" protested a voice "i wanted this to be a surprise!! now, you've ruined it, announcing on HN...", "rhoo, it will be fine!" reassured another)
As far as I have explored the subject, the support for playing with the computer keyboard will probably be restricted to "simple plucking" (no support for "press and hold", and no velocity).
For keyboard expression, it will be simpler to just use MIDI input.