There's a HARD level set!!??
I won! All 40 levels ... only to discover there's an alternate level set that's labeled "Hard".
O_o
Fantastic game design. The user interface could have used an "erase this block" button instead of just overwriting. The music loop would have been better if it were longer, but the content of the music and instrumentation itself were great. ... I may have to actually do the hard levels now ... dammit.