Great work! I liked the idea of switching the size by timer, rather than by a separate button. Because of this, in some places you have to stand still, waiting for the size to switch. Then you start going through this moment and try to go through it in one size change so that you don't have to wait for the transformation again. Because of the rush, you lose and start over. As a result, the main obstacle for the player is not the difficulty of the level, but his own haste, which I think is very cool.

As for the mechanics, you can add some kind of bonus for the large size. The small size allows you to pass through low passages and walk through narrow places, and the large size only allows you to jump harder, as I understand it.

And of course respect for making the game not super easy. Interesting challenge!

I really enjoyed the art style and the skybox. Very cute! Enjoyed the little size based obstacles too like the crumbling blocks when you're large. Nice work :)

There were some cool ideas in here, took me a few tries to work out why I was dying in the tunnel!

I loved the concept of the forever changing fairy size keeping you on your toes, well done!