Its okay for a few minutes, but then it just gets repetative an boring. There needs to be an actual goal, a way to win, maybe at least some little bit of story. Just an endless fight with no purpose? meh.
A few of the medals dont work, the one for breaking all the pottery did not unlock, and the one to make the hydra fly did not unlock. Vandal unlocked normally. Also, how do you get the key in midair? The key spawns on the ground, its never in the air at all to catch.
Finally, there really needs to be some in game clue as to how to unlock the special mode. There is not even any mention (other than in the medals) that there IS a special mode at all. Your clue in the description does not help at all. I had accidentally found the area under the room before fighting even a single time, but I have no idea how to open the *door?* down there. Again, there are NO in game clues at all to it.