Most of the mining equipment from Dead Space, the ripper, the line gun, the force gun, the plasma cutter (my affectionate favourite) all these tools were insanley overpowered. Making the hideous alien monsters spawned from fresh corpses look pitiful and weak by comparison.
Ironically the only actual WEAPON in the game was practically useless for the most part.
I've also resisted the urge to mention my beleif that in Halo 3 at least every weapon is balanced completely fairly, because I vowed to make less Halo themed posts. See I'm learning give me time and you will see results!