I'm not good at puzzle games, nor stealth games, so this is a tough game for me. In any case, the level design and the map elements really stood out to me. I think the visuals and the music really fit well together, and the game feels really intense. Also 15 levels is very impressive.
The sound effect for the green enemies was neat, but I think the effect would keep going even when I stepped off the aggro zone.
Also, I didn't play the later levels, but I was very excited thinking about the levels that would combine a lot of the elements introduced as the game went on.
Great work!