Nice work! I have a fair bit of experience with platformers and was able to make it through this one without too much trouble (did die twice though). The graphics are charming and on-theme. I enjoyed it.
If you want critique on the level design: in terms of gameplay pace, this feels like more of a Mario than a Super Meat Boy, so my gamer brain expects every hazard to be telegraphed early enough for me to feasibly react to it the first time. That is to say, this feels like a game I should be able to win without knowing the map, if I'm a sufficiently good player. There were a few spots here (the cloud in level 2 shooting out of the narrow passageway got me the first time) where I think a hazard appears too fast to react unless you already know it's coming.