This was absolutely amazing
I just found the difficulty kind of annoying with how you had to start all over after loosing once.
That and the fact that taking blood takes about 2 seconds to get started made me not entirely finish this, though I think I got to the last boss.
On that Boss the Blood healing seems like it'd be the most fun to use, however I couldn't find any timing window which gave any meaningfull amounts of blood. I bet I could if I would restart the boss instantly but I guess that doesn't happen (correct me if I am wrong, the game had a crash when I dies on it).
Anyways, that should in no way distract from the fact this is amazingly made. Really enjoyed my 1 hour with it.