The hit rate and block rate is completely unbalanced. A high block rate on opponents shields, then Shield Bash means their block is like that for 5 turns, and the 30 MP cost is negligible.
What the hell? If you lose you cant actually win. You dont get a chance to improve, so you are fighting it over and over, and if you cant beat them you lose. I was on wave 15 and couldnt get any further.