I might've done something wrong, but there doesn't seem to be any danger - I wasn't hit once and I won. Also, some cards are not really usable, since I've never gone over 5 mana, and some require 10 or 15 mana to cast - seems a bit weird.
The UI is also covered by itself, I wasn't able to see how many cards I have left (1440p screen, 16:9).
Seems like a cool idea, but there's not much game there yet - needs more stuff!