I like the idea and implementation, idk what else to say it's pretty cool how you are stronger on the one side but the enemies are harder as well.
critic points:
- 3 minutes are WAYYYY too long (maybe it isn't for you as a developer, but for everyone else it is (the 3 minutes could be a hard extra mode if you want))
- (not necessary but would be cool to) make the dangerous rocks more clearly visible and dangerous
- other points are already mentioned in already existing comments