It's playable, but I don't know why you'd want to. Even post-patch its still a mess. It's still far uglier than the trailers, the AI is still incredibly dumb, and the only real bug hunt you'll be going on will probably involve support forums.
You don't even fight Xenomorphs for most of the game. The vast majority of the enemies are generic Weyland/Yutani mooks.
Oh, and O'Neil. Seriously, fuck that guy. He's got a goddamn Smartgun and can't even hit the broad side of a barn with it. IT AIMS FOR YOU! ...Oh God, no... he heard me! I'm sorry I offended you, O'Neil.... please, please don't stand in that doorframe and refuse to move! Will you move if I tell you that I really like your voice actor? I mean... I liked you better when you were Colonel Roy Mustang, but... OH GOD DAMNIT, O'NEIL! WHY ARE YOU SHOOTING AT THE FLOOR?!