Too many cheating fighters. They are beyond broken, they are basically cheating. Edit: For example, in Holodeck Hazards expert diffculty, if you are faced with Meow & Fewer or Freedom Fighter, it's basically a defeat. At least make those heroes counterable with play strategies, instead of requiring certain fighters. Tres Chic is a good example: She is counterable, by staying at your own side. Or Untouchable: When she gains unflinching, player can confirm a BB.