Thanks for playing!
The mouse movement being overpowered is something that's been brought up. I tried designing each level to be beatable with all three movement modes because I wanted the game to be accessible to those who couldn't figure out how to use mouse move mode. But since a lot of the levels require you to move over long distances to get between safe spots and mouse move mode is so much faster than either of the other two movement modes, a level that would normally be hard with either of the other two movement modes will almost always become a joke with mouse movement.
If I were to do it again, I probably would have designed all the levels to require more precision manuvering. Since the main strength of the mouse is being able to move very fast, this would have made it less overpowered without making things more unfair for the other movement modes.
If you want the game to actually be challenging with mouse move mode, hard difficulty might be up your alley. :)