The changes to the predator race include a new effect for headbiting from the predalien perspective; think the structure of a predator's jaw to get a sense for how this looks. The predator's new energy flechette is a rapid fire alternative to the plasma cannon, their equivalent of a submachine gun. In multiplayer games, the predator's self destruct option kicks in when he's badly wounded (it was raised from 10% health to 20% health after Third Law discovered it was too hard to use when you're that close to death). Using it will cost the player a frag, but the penalty is worthwhile if you can take out at least two other opponents.