YOU would have thought that aliens would have learned their lesson by now. Why when invading earth do they pick on America first, the largest stockpile of armaments in the world?

Battle: Los Angeles features a bunch of pressure-cooker headed aliens short on intelligence, but apparently better armed than we are, who decide to lay waste to one of the most well defended areas on the planet.

With most of LA reduced to smoking piles of rubble and burnt out cars in the first 10 minutes, it’s up to Staff Sergeant Nantz (Aaron Eckhart) to lead a team of largely anonymous grunts on a ground mission to rescue some civilians before an incoming airstrike wipes Santa Monica off the map completely.

Alien invasion has been a stock genre for decades; you would have thought that writers would be able to something new with the material or at least stick to what works.

News Shopper: MOVIE REVIEW: Battle Los Angeles ***

But the aliens in Battle LA are unimaginative walking tin cans that function as targets for faceless marines to take potshots at and when stripped of their armour are nothing more than squidgy bundles of tentacles.

For such a big-budget movie, there’s very little spectacle. Admittedly the aerial shots of LA burning are quite impressive and manage to convey the enormous scale of the devastation but for the most part, grey marines take cover behind bits of brown wall and exchange small arms fire with grey aliens entrenched behind piles of brown scenery.

News Shopper: MOVIE REVIEW: Battle Los Angeles ***

The weaponry isn’t even inventive – no plasma cannons or laser rifles here - replace aliens with marines and it could quite easily be mistaken for the urban combat zones of Blackhawk Down.

Roland Emmerich wouldn’t even roll over in his sleep for the small scale explosions on offer.

That’s not to say there’s nothing to enjoy - some of the fire fights are tense and exciting and the pace is constantly brisk.

News Shopper: MOVIE REVIEW: Battle Los Angeles ***

Aaron Eckhart is carving a name for himself as one of Hollywood’s most reliable actors and fits the part as a grizzled, stoically tough marine surprisingly well, even though he’s saddled with appallingly clichéd dialogue.

Of particular note is a grandstanding speech he gives about duty and loss, which begins to be quite moving only to be brushed away dismissively with “But none of that matters right now” – a hilarious line that could have been come straight of Airplane!

For the most part, Battle: Los Angeles is one sequence of action pieces after another. But with no characters to care about other than Eckhart, who according to screenwriting 101, is either going to save the day or die heroically while saving the day, it’s hard to care who anyone is, let alone give a hoot about their fates.

News Shopper: MOVIE REVIEW: Battle Los Angeles ***

Plenty of the film seems to exist purely for filler. After capturing a wounded alien, the squad spend a good 10 minutes trying to work out the best way to kill it.

But the information’s completely irrelevant since the walking tin cans seem to go down just as well if you shoot them anywhere or if the team blow them up with the copious amounts of ordnance they seem to have to hand.

It’s a competently acted but poorly scripted action movie; a film with the subtlety of a brick that delivers big-screen action bombast but lightweight emotional drama; one about as two-dimensional and forgettable as any of its marines or the saucepan-headed aliens they’re up against and one that delivers disappointing little bang for your buck.

Battle Los Angeles (12A) is released on Friday.