=) I noticed that when evaluating Arduboy 2, but with the short timeline, we made a decision to stick with Arduboy. -- Keep in mind that we went to "production" 1st week of December 2016.
Great observation about the notes. This is one of those "hmm... that shouldn't really work" type moments.
Quick back story:
While developing the game, i was noticing that the platform was restarting music way too early. That is, the last note length wasn't being honored by PlaytTunes. So... The dirty hack was to throw in an extra 3rd note, and somehow that got the music to sync better and not get re-triggered too early.
-- Strangely enough, i had issues where notes were being dropped from the score as well.
It's visible in the committed stage1.mid file, IIRC.