An awesome concept that needed a bit more work on the execution. It took me several minutes to realize I needed to eat a treasure before eating the hero---that part should be explained to the player in game, or at least on the game page.
As far as the gameplay goes, I had some fun, but overall it was more frustrating than fun. The hero moves at lightning speed compared to everything else in the game, so it's really difficult to position myself in the right place before he sees me. I gave up on level 3 because although I found a good hiding spot, the devil kept running up to the hero at my spot, getting us both killed.
A higher move speed for the mimic would have allowed for more active, "cat and mouse" strategies while also making the game less frustrating.