I came to also mention that you can move and shoot the last boss before it is able to move. If you do so before the health fills then it stuns it into place. If you keep firing until its dead then the game soft-locks anyway. You can use the menu exit to get out, but I had this accidentally happen to me.
Another bug is in Subterra Scorpion's stage there are some missing assets in the corners of some slopes you can slip through and end up in spaces you're not meant to be in. I've usually been able to squirrel my way back out of them, but should be a pretty easy fix.