Thanks for the feedback and glad the Linux build was helpful!
First time hearing coyote-time and looking it up sounds like a great idea thanks, it definitely sounds like something you would want in all games with this movement type!
The apples were meant to be an easy way to clear a level if you had trouble but looking at it again definitely 1 apple is enough.
You can reset a level by clicking 'R' and return to the menu by pausing and clicking 'M' but it looks like this wasn't obvious and not user friendly something we should address.
Difficulty were ordered based on perfect clearing (Collecting all the mice) but the better solution is probably to have normal clear and perfect clear kind of equal so that order works both ways.
All great improvement ideas thank you for the detailed feed back :)