Hi, quite a cool unique idea, good cassette and background.
The intro was quite long... nearly so long that I would quit.
Cool that you had a tutorial to explain it, but i still didn`t really get it 100%^^
Had trouble after the second song and there I quit because it was not very satisfying for me to play.
I would think the biggest improvement would be to have some UI Sounds (clicks, rewinds etc) also at least invest 5 minutes a few nicer buttons and text labels and font. I couldn`t really look at that ugly text. at least give it a outline or something ;) because is think the artstyle of game and text clashed, and didn`t fit well together.
I think you system build around the music is very cool though