Great idea, good execution
Here's my one nitpick: As someone who was trying to figure out the puzzles just based on the music (I knew most of the tunes), Yankee Doodle is a disaster. The melody in the game isn't even the melody in the tune, and many of the accompaniment parts don't seem to fit at all. Also, I agree with not spoiling the surprise as far as what we unlock at the end, and I don't understand how I completed the game with still a "1" showing in the first room, which by the way it wouldn't let me go back to after I unlocked the last thingy. Oh, and I don't understand why you show 5 rooms on the mini map and only use 3 for the game.
Otherwise, great concept, fun game. Something actually original and fun to play. Keep it up!