Wow it's hard to test your own game and understand its relative difficulty after staring at it for 6 months!
From the handful of people I've seen play SongRunner so far, it seems like it's just a bit tougher than I intended. So making some adjustments here.
some screens in level 3 were adjusted to be less annoying
added a restart icon with a tab hotkey to the main game's UI
restarting a level is also way quicker now
couple of small bug fixes