Dumb science fiction is sometimes fun. The first Transformers film was idiotic, but a real blast to watch. Hell, even Star Wars is pretty dumb, but it's one of my favorites.
And the science in a movie can be really terrible and still allow for a great time. The Matrix, for instance, makes no sense whatsoever, but I love it.
But even good science couldn't save a shitty movie, and Battle: Los Angeles is one of the shittiest I've sat through in quite some time. Laughable science is the least of its problems.
Taking its cue from a multitude of "bad idea" science fiction, the invading alien force eschews any sort of logical plan in their invasion of earth. In point of fact, they seem to have read the playbook of every poorly-planned invasion of our planet since the dawn of cinema. Two films in particular seem to have inspired them:
Independence Day: "Hey, let's rig up all our spaceships so they take energy and commands from one central hub, which the humans can't possibly destroy in a heroic third-act push."
Signs: "Sure we came light-years to attack this planet, and our technology is vastly beyond anything humans can even comprehend, but how about we run around on foot and kill them one by one?"
Why are the aliens here, you ask? Well, to save you the trouble of watching this ham-fisted, dull, and horribly unimaginative movie, I'll just tell you: They want to steal our water. Because, you see, Earth has it in liquid form.
Yes, you heard that right. These aliens are advanced enough to haul hundreds of thousands of tons of soldiers and equipment (at the very least) across the vast emptiness of space, and ruthless enough to obliterate an entire native intelligent species, because they apparently don't know how to melt ice.
Alright, so they need liquid water (a preposterous amount of it, as one idiotic "science-y" bit would have us believe that the ocean levels are dropping perceptibly in the few hours the aliens have been attacking). So, of course, the FIRST THING the aliens do when they have landed all their invasion forces in the ocean, is tromp out on land, attacking every major coastal city in the world (apparently --though only a dozen or so are actually mentioned, San Diego, San Francisco, and L.A. all get the treatment, so it has to be pretty widespread).
I know, I know, movies like this aren't about logic or interesting ideas -- they're about entertainment, right? Well, maybe movies like this, but not this one. This one commits every major sin a movie like it can possibly commit.
It is populated entirely by forgettable, one-dimensional soldier stereotypes (the rookie, the tough chick, the guy with a chip on his shoulder, the inexperienced officer, and, of course, the grizzled veteran -- in this case, Aaron Eckhart providing the grizzle). And alongside them are two children and two civilians, none of whom do we care about even a little. It wants to be like Aliens, where each soldier had a personality and, while we may not have become too attached to them, we at least knew their names, but instead it is like ... well, like every bad attempt to copy Aliens of the last two decades.
Its true sin, however, is that it is booooring. The battle scenes are Blackhawk Down-wannabe kinetic craziness, but it never manages to be even slightly convincing. The characters do a lot of talking that is clearly supposed to be "character building" but really just seems to lengthen the amount of time we wait for anything to happen.
One scene that seems to go on forever involves a field vivisection of a wounded alien in an attempt to find it's "weak spot." The intrepid soldiers divine that they should shoot the aliens "just to the right of where the heart would be," which one would assume would be sort of the default place you'd shoot anything that looked vaguely like a person. They proceed to tell the rest of the marines this important tip, and then everyone proceeds to ignore it for the idiotic time filler it is and run them over with trucks instead.
And the aliens are boring, too. We see a grand total of maybe five variations on the attacking forces: soldier, leader, "tank thing," aerial drone, and mothership. We never learn anything of any significance about the aliens, except that they are terrible at planning and carrying out invasions. They have no personality at all and they don't even look particularly good.
I've heard that the company that made the reputedly-terrible Skyline ripped this movie off somehow, but honestly I don't see anything at all worth ripping off.