Nice little game, the main idea is really good, I like a lot the interaction with the spring (the longer air time not allowing you to flip for a while). The backgrounds were very pretty, the audio was really good and the sand indicator was perfect (same for the border of the screen turning red when we don't have much time left)
I have a few issues with the background, it moves weirdly when we are to high / when we stop moving. There is also quite a lot of time where I went out of bounds (the don't jump lv for exemple it is really easy to die in the top and break the background).
I also feel like the "tutorial" levels are not great. The first mandatory jump of the game being one on the on/off platforms is really weird to me for exemple. I also feel like these are too short, only showing the most bare bone use of the mechanic.
But other than that I had a lot of fun playing, the game has a lot of potential for longer level combining the mechanics in some clever way.