This was great!
There was so much play to the rock mechanic! At times it was like Breakout and other times like Bowling! I really liked how it affected my movement (and I could use as a platform!).
I really liked when I’d managed to weaken a bunch of enemies to the point when I could kill multiples in one throw, that was great!
As for criticism, I guess it got a bit tedious when every enemy took multiple hits, and progress got quite slow (because new waves came in before I could deal with the current one).
Maybe retraction speed could scale up, or something (maybe it does, and I just didn’t notice/find it).
Anyway, awesome game, and the core mechanic was very inspiring!