It annoys me how even if you hit a ninja with a top level mana drain crypt and disarm it (Hell, I've even disarmed and frozen it in all 3 of a crypts charges) it STILL cloaks for 5 seconds when it's unfrozen, meaning the disarm was completely useless. Disarm seemingly only stops it using it's ability again rather than disabling it from when it hits. Annoying.
One problem is find is that it's almost a gamble when you select a stage. Ok so you have the recommended element as a guide to at least one element to bring, but sometimes around 1/3 of enemies can be of an element you're totally unprepared for and just demolish the defenses you have set up. The same is true for flying enemies, of which you're given no warning of before you enter the stage.
 "Cursed Treasure: Don't Touch My Gems!"){kind=icon}
 "Protector IV"){kind=icon}