You know it's fun if you can't put it down till you beat it! For me that mean spamming restart until I could clear a path without spending a fortune on the magnifying glass. That didn't feel right- but us goblins don't have time for your rules, we have gold to gobble.
Mimics being towers didn't feel right- I think it would be better if you just discovered that that rock was indestructible or something.