This was a reaaly nice game! Loved the artstyle and gameplay gimmicks.
Level design is ok, but invisible walls in certain places make it a bit hard to navigate, and I wish there were shortcuts at the end of each world branch, to eliminate some of the backtracking. Also, while the camera switch triggers work well when you're going through the level forwards, but if you're going backwards, they have a tendency to get quite awkward, to the point when you have to go completely off-screen to reach them. This only really becomes a problem if you die and enemies respawn behind you tho, so it isn't really that big of a deal.
Still, I really enjoyed playing this!