I just fought a Gloomstalk guardian in some catacombs. It has an ability called Doom Blaze which is "limit 2.5 uses per combat". You might want to check that. ;)
It would be nice if Aces counted as either 1 or 11 for Perfect Kills. It's noticeable with the new bard character. If an enemy has say 6 health and you kill them with 5,A on the Scythe, it doesn't give you a Perfect Kill as it automatically deals 16 damage rather than 6. In other places in the game A can count as 1 for making up an exact number to activate an item, so it'd be nice if perfect kills matched that principle.
The wizard seems the coolest character. I want to play her. Sadly, she can only play the first world. The big boss (hexagon) is hard enough with other characters: trading punches as it sets everything on fire. But being able to hex everything every turn for free completely nullifies the wizard's playstyle which relies very heavily on storing cards, which you can't do with the constant, unavoidable hexing. If you use your storage, you don't gain anything and are just gifting cards to the enemy!