The art looks great and playing through the levels was a lot of fun. The story narration in the background was a nice touch. It made the game feel more unique. Personally, I enjoyed the later levels more than the first few because you made better use of the switching mechanic and the different characters in the level design. Some of the earlier levels just have the player go through them twice as the paths for the two characters are too similar. If you want to keep developing this further, different abilities for each character could be something to look into. It would make each character feel more unique and allow for more intricate puzzles.