Someone spoil the ending for me, I'm slightly curious. :P
The aliens win, the military is defeated. Everyone but the protagonist and his girlfriend is killed through the course of the movie. Our Hero is abducted and has his brain sucked out of his body and installed in a monster, but through repeated exposure to the alien Mind Control powers he's gained immunity and instead takes over his host. In his new alien body he finds his girlfriend in the bowels of the ship, picks her up, and... roll credits.
I hear there's a sequel in the works.