Excellent point. I know it was a byproduct of trying to disallow multiple notes playing at the same time (no chords on a trumpet!), but when all you can really do is hold the trumpet and push the valves, it reduces responsiveness quickly.
A post-Jam update would include a UI to indicate the note being played, maybe simple instructions on the most basic of trumpet songs, to enable those that have never played one, to noodle out a track. As it was, I was reaching back to my youth, playing trumpet in high school band. Thank you for playing my entry, and for great comments! I may have been missing the music in your entry, but everything else about it was really stylish.