Hmm, a cute, simple game. It's a very competent execution of the character-switching platformer. I especially liked the mirrored invisible room.
I couldn't progress past the third level. It becomes locked upon exit. I can't tell if this is intentional or accidental.
The settings button and locked level buttons produce a piercing, annoying noise. I think that should be something different.
The art is mostly charming, but Yellow's awake face is strange. While blue is very silly-looking, and yellow is cute while asleep, yellow's awake face looks like they're about to eat me. The combination of black circles around the eyes with tiny pupils make them look quite scary.
Good attempt! Congrats on submitting!