(Disclaimer: only played the first zone before calling it quits)
The propeller hat was fun, if a bit annoying at times. Liked the little spinning animation. Flying through the levels would have probably have looked cooler if played by someone better at platformers :)
Did not like how the screen would glitch up and down a few times whenever I died (and that happened a lot). It got to the point where I dreaded the glitch more than dying. Also at some point I thought I was softlocked when the camera was on the previous level. Turned out I could have fixed it by walking back and forth, but there was a spike pit that I was falling into in the level I couldn't see.