I don't think the humans are as helpless as everyone makes them out to be, considering they are the only ones with any real effective ranged weaponry (The Predator's shoulder cannon takes too long to lock on and is worthless in tight corridors, and the throwing blade can be seen coming from a mile away) As an Alien or Predator I was constantly getting torn up by pulse rifles left and right due to the high clip capacity of it. Not to mention the shotgun's alt fire wipes out anything close in one blast, and the Smart Gun does all the aiming work for you and picks up most far off targets in the dark. The flame thrower and sniper rifle were crap though. In TDM I can see a pair of humans watching each others back being very, very hard to take down.
I think the demo was somewhat unimpressive, but I'm not going to dismiss the game yet and wait until some reviews pop up to decide whether to pick it up or not. I just think the demo that was released was the worst possible way to represent what the multiplayer is capable of. Its a dumb idea to only showcase individual deathmatches, in a very generic, confined, and uninspired map no less. Kind of undermines the whole species vs. species premise and strategy when every creature is out there for themselves stabbing each other in the back, literally. Hell, half the time I died was due to being killed by the same species. Throws the whole rock, paper, scissors balance of the three species off. Anyway, the multiplayer reminded me a bit of Splinter Cell: Chaos Theory, and I'd love to have an experience like that on the 360.