Overall a fun and moody puzzle game. I thought the laser mechanic was really interesting and allowed for some cool puzzles.
If you wanted to improve, I suggest some sort of sound effect for when something is triggered, it would help the game feel more responsive. You could even layer another instrument on top of the piano to get the effect of slowly building up to something. Also, the player character felt really slow, that may have just been my PC as it is older.
Overall, cool game!