This is basically a poor man's Independence Day, minus the charm, fun, and epic speech scenes. The only thing this movie really has going for it is the effects, which, to be perfectly honest, don't make it worth seeing.
Pretty much every aspect of this movie is mediocre or worse. Honestly I'm a bit amazed that this was in theaters, rather than debuting on TV as a Sci-Fi channel original movie. It would have been their best movie every maybe, but if you've seen any of their movies you know that isn't saying much.
The aliens' motivation is never made clear, though they seem to like BRAINZZZ...maybe they're zombie aliens. I did think the ending was kind of neat, though, and one of the earlier scenes involving a stealth bomber was good. But those were really the only positives I got out of this.