I'm not gonna lie,  I didn't play it TOO much. I only gave it 4-5 tries, but I really liked the idea! As for critic stuff, I'd say it's a little too fast/too hard. Enemies cause too much damage and you don't heal enough. I like the challenge, and this definitely seems like that kind of game, but it should give a little more room for mistakes.
I know that it's a "super early alpha demo." xD

Anyway, keep up the good work, and I hope your game goes well!