The only new thing was fire resistance...and yes, it was berserker bloodlusted creature. The fact that J'onn had little trouble undoing the Fernus' telepathic mess afterwards speaks for itself. In fact, in some cases it was actually DUMBER than normal J'onn (Burning Martians operate mostly on instinct, part of devolving by Guardians was to give them the ability to think rationally).
Otherwise, I can't remember any feats outside of J'onn's normal powerlevel (not personality, as pacifist gone berserker is definitely going to have different attitude).
I feel the fight with CIS off stipulated will be more interesting.