+1 on tutorial interaction (which is a bit funny comming from me since i have 25 review on my game that begin by "did not understand a thing at first' ^^, so yeah not the greates exemple). But intereaction is always great to help the learning curve, other wise it is a bit much.
Great choice of music btw ! Very soothing
Gameplay wise i was harder for me since i have a french keyboard, but i liked running arround to catches each letter, good rythm thougout each level. also.