Simple concept yet really fun
Despite being a very simple game (and me very quickly falling into a rut of leech-stun-rinse and repeat), it stayed surprisingly entertaining all the way through. I think part of this is that there's a definite goal (being able to see the % finished was inspiring!), death is cheap (so even though you try to avoid it, it's not the end of the world), and it moves very quickly. I also liked the wide variety of monsters, even in a single level.
It's funny, I started off doing pretty easy, hit a part where I was having some difficulty, ended up leveling off at "hardish but not that bad", and then suddenly it got really easy toward the end. Probably because I put some points in speed and leveled up all my gear. The end was still a little bit of a challenge (or at least I had to keep on top of my health) but not all that hard.
tl;dr version: very fun and didn't get repetitive, even though it seems like the sort of game that should. So props for that. Also, nice monster design and I liked how quickly and easily the game flowed.