Great game, took note of 3 suggestions for you (v4.1)
- The restart button turns blue forever after you restart any level once. Seems like a bug.
- When my character dies, there is no sound at all. Seems like you missed adding an audio source for it.
- In the second-to last level, there is no indication that the propeller can be used to throw objects . It's a good puzzle but maybe you can add an intermediate level where the player is forced to discover this interaction by accident.