Overall, a fantastic little game. Great story, simple, clean graphics, fitting music. The only issue I had was that the hit detection seemed to be a little loose. It seemed like after I died (during the invulnerable phase), I could get right up next to a red block and still be alive when the invulnerable phase ran out. If I tried getting that close after I quit flashing, I'd die. Nothing horrifically distracting, just a little inconsistent, I suppose.
Oh, and the "You always make me laugh" room made me want to hurl things across the room. A terrible, beautiful, difficult room.