Loved the art, the sfx and the very cool shadow mechanic. You have some great puzzle design in some of the levels, but the difficulty curve is all over the place. Some of the last levels where extremely easy and some of the levels in the middle were extremely hard.
Also, as a little constructive criticism, the vent does not tell the player it is the goal, it just blends in with the environment. Normally it is a bad idea to use the same color as the walls or the floor for the end goal. Also, the way the enemies kill the player fells kinda unfair, they just teleport to you, it was maybe done for balancing or difficulty purposes, but maybe next time try to look for a way to justify it so that it does not feel like the enemies are just cheating to get to you. Other than that, is a solid short but cute and very well design puzzle game. Well done <3