Demon skill description is wrong, received damage isn't 40% but 20%. Not to mention 25% healing nerf. You also refer to blue bar as SP but sudennly it's mana for demon.
Items give a lot of different bonuses and it's good way of customization but game fails when it comes to character description. "low hp", "increased crit and resist", "poisons", whole Land of the Dead description, "slowly heals the hero". You stuff items with numbers but we don't have numeric values for class base stats and skill damage/heal.
Life Branch weapon says about 20% crit but is it crit damage or crit rate?
Sorry about long wall of text but seems like kongregate cannot into text formatting in XXI century.
Flying isn't really flying, creature that flies isn't supossed to get hit by non-flying creature. Does it have any function here? Same thing goes with Slow, "Slowed creatures can't attack", yet they still do attack when it comes to battle creature vs creature. Stupid. Also, i think you got Core Silver and Core Gold packs wrong. Silver gives 1 common card more and has bigger chance for rare card, at least description says so.