Well all artillery and destroyer are a problem when they're controled by the AI lol. In fact my biggest problem is the Katyusha with her multi shots, last time 4 tanks in one special, including my super pershing lvl25, a joke. Not including the fact that we can't set a priority to where the damage can be done, yes i'm looking at you arti or destro behind set up bunkers ^^
Can do lvl28 if the boss is not the maus.