The biggest problem with this game are the bouncing projectiles. They add lots of noise to the game. If it's bouncing past me I have to takes me a bit longer to confirm that I'm shooting in the correct direction because I can't differentiate bounced from directly shot projectiles. The other problem is that none of what I'm doing is intentional. My projectiles bounce, it accidentally kill an enemy and the level suddenly ends. It's jarring each time it happens. Having a shoot button might be a good idea to consider to make each action more intentional and picking what you actually want to destroy.
The levels stretching full screen might be no good. You should add walls to the edges, which give the play area some margin, adds a nice framing and prevents UI from covering other important things.
Having secret exits from levels is cool, although mostly because it reduces the pain of having to replay the levels.
White jungle was really confusing. I had no idea that I could destroy trees and it just opened the door for some reason.
I gave up at the leaper, I didn't want to replay all those levels again after game over.