I enjoyed this! Two small things:
I think the penultimate level might have an unintended solution – you can basically walk straight to the exist after you've pushed the first rock on square.
In the end the couple of levels before that one feel like the apex of the difficulty curve and the last two levels, despite looking complex, are less conceptually difficult to solve.
Good job though, it's a cool mechanic and the movement is handled really well :)