I saw the trailer and, it shows 2 new aliens: the one already shown (The Breeder) and another one called Phantom (assuming that's how they are spelling it). Phantom looks cool. It basically jumps around a lot, or seems, and then also teleports, kind of like Night Crawler from X-Men. Not massive teleportation, but just little bits from area to area.
The new gun that uses scorpion venom seems like it could be cool, too