I really like the level design and the art, it was fun to play.
The individual animations for the character are great, but I think if you make transitions by blending between animations it will feel even better.
It takes too long when you move the camera to show the door to be unlocked. Unless you're going to have something interesting happening at the door it's probably unnecessary after the first time, as the player already knows what to do. The animation for using each keys to open the door is also too long especially for the second door with 3 keys.
That's all the feedback I got, hope it helps!