Thank you for the thoughtful and kind feedback! It's always great to meet fellow Jazz musicians!
Honestly, not starting on beat 1 was a design decision. My focus was to start at the beginning of a phrase, even if that meant starting in the pick ups. I figured it would help out non-musician players who might not have a running metronome in their heads like we do :P
You don't happen to have an HTML5 build of your game do you? I'm on a mac..