I am not really sure what the plot of Battle: Los Angeles was. There where lots of explosions, some very loud noises, and excessive queasy-cam movements. Every now and then Aaron Eckhart would yell at his platoon, Michelle Rodriguez would curse in Spanish and another explosion would happen after that. The rest was a blur.
We know from the trailer this is a movie about the Earth being invaded by alien forces. The events are seen from the point of view of a single platoon fighting in Santa Monica (no, technically it is not Los Angeles). Aaron Eckhart leads the platoon in a role so anonymous it could have been played by anyone. The aliens rapidly overwhelm Santa Monica and the platoon ends up behind enemy lines. Not a good place to be. This could have been a really exciting film if we cared for any of the people who need to survive. But the action sequences goes on for so long that we end up wishing they die soon just so the film can end sooner.
Yes, explosions are pretty to look at; doesn't mean they are good.
Very few movies manage to have characters as anonymous as Battle: Los Angeles. I have seen movies where the characters are cardboard cut outs of established stereotypes. But even in those cases I end up caring more for the characters than in this movie. Here they are all uniformed men shooting at an unspecified mechanical enemy. What is the point of having Aaron Eckhart in your movie if you cant tell him apart from the guy playing Soldier #4 in the background. Michelle Rodriguez stands out a bit more; because she is Michelle Rodriguez and underplaying is something she is not capable of.
So the platoon marches on trying to make it back to forward operating base. At some point a newsreel informs us that Los Angeles is the last stand for mankind. If Los Angeles falls we are all dead. The thing about LA is its build on a dessert so it is not self sustainable, so if you take it out everything around LA, LA goes along with it. It makes a very lousy last stand.
The film however does have some technical merits. The photography is stunning and it does recreate the look of some of the best war movies out there. The staging of the battles is also really neat, and LA is recreated successfully enough that it is fun to see it wrecked. And the crew probably had a lot of fun paying Godzilla on their models, whether practical or CGI. But it is not enough, without the very basics of character or a hint of a story line it is really hard to tolerate explosions for more than twenty minutes or so.
Maybe Battle: Los Angeles was meant to be short movie. Here is another idea; expand it. Make it into a multi-episode series, and fill in with flashbacks set before the invasion. That way we have time to get to know the characters. Anything could have been better.