Nice little puzzle/ platformer, I could complete all levels! The rules and reduce size ability are explained quite well in a progressive manner, and the build up in difficulty is also quite smooth.. the last level was definitely the hardest! I also liked the fake platform concept, did not feel unfair at anypoint.
One suggestion i would have is to some animations or effects on landing of the ball on platforms to make it smooth and things like when the level is complete or the red things hit the ball etc.. that kind of feedback would enhance the gameplay a lot in my opinion. Also the speed of movement could be reduced a bit. I got used to it as i played more, but initially it was a bit difficult to handle Overall Nicely done!