Oh for the everloving love of . . . I'll never look at a checkerboard without anger again. Annoying, yet somehow addictive enough to have me play to the end. 4/5
I'm afraid I don't have much to add beyond what others have said. Excellent concept, what appears to be fine gameplay, but the system is cumbersome and unless you know how to write music or just really dig into the mechanics and turn your speakers off, it's not really all that fun, it's just random and repetitive. Now, for the musically inclined, this must be really neat, so kudos for making a game for them. It just isn't accessible.
Since you asked, my problems with the collision: First, getting hit by a slime I wasn't anywhere near. Second, getting trapped on a corner while trying to jump up one of those center-column jumps. Also, I'm not a huge fan of areas with jumps way too high to get to with a starting character and making them tall enough you can't go down by the time you see the height of the jump.
Somewhere between good and great, but it's too long to start over every time for the happy/unhappy temple endings, the suicide, the suit and the beacon.
Otherwise very nice.
Looks like your fire rates are based on a timer rather than a frame, and your movement is based on frame rate. This means if you bog the system down you get a wall of firepower around you. Just FYI
Strange, I actually did better when I stopped caring about getting notes or listening to the music. I went from zero birds in state 2 in 8 in stage 3. I guess it does teach you about relaxation. ;)