Cool idea, great visuals and atmosphere!
The movement feels a bit stiff though. And if the idea is that you get weaker, shouldn't the enemies also get weaker so the difficulty stays the same? Or maybe they get slightly less weak so it gets a bit harder? In general it felt too easy because if you keep lifesteal and armor you can just stand still and spam attack (although I did not finish the game because I wasn't sure how many levels there were, maybe this could count down?). So maybe the upgrades should be less good than the downgrades?