It hasn't been a good year for alien movies.

Together Cowboys & Aliens, The Darkest Hour and Skyline were bad enough to make the collective argument that humanity deserves to be lasered, vaporized and brain-harvested.

Of course, that requires that the alien forces are ruled by the brain-bonded pair of Roger Ebert and A.O. Scott. That's what I always assume. When they come to punish us for those other bombs, however, we will be able to hold up 2011's Attack the Block in hopes that it is enough to be spared.

In South London, a teen street gang led by John Boyega has a run-in with a violent but lone alien. They dispatch it handily enough but soon find their apartment building beset by a plague of much larger and nastier interstellar monsters.

A British action-comedy, Attack the Block makes what might be the world's first argument in favor of gangs and juvenile delinquency. While most reasonable, nonpedestrian-robbing people would run from big-fanged horrors from beyond the stars, Boyega and his crew cheerily grab bats and katanas and rush off to show the aliens they should consider invading a place where the property values are a bit higher. Like anywhere.

Attack the Block supposedly was inspired when writer/director Joe Cornish was mugged by a similar gang. If so, up with hooligans! Apparently directors will readily make funny, colorful movies if you just threaten their lives hard enough. Hollywood is just a few miles from "urban" Los Angeles. Let's make this happen.

Yet Boyega and his boys are hardly hardened thugs. They are scared to rob nurse Jodie Whittaker. They terrorize the neighborhood on bikes. They regularly check in with their parents to lie about where they are. Even when they are saviors, they're treated like scum by the cops and neighbors. Sci-fi and horror regularly provide the bulk of our social satire, and it is a good thing we take it so seriously. I don't know whether we would have all this peace and prosperity without it.

Cornish's light mocking helps round out his characters, but not all of them emerge as anything more than cannon fodder. Or more accurately, as eyeless gorilla-wolf fodder. Also, his color palette is that orange/teal contrast that has apparently slept its way into appearing in every movie of the past three years.

Still, Cornish's jab at Signs is worth admission price alone. Which is probably zero, unless you charge yourself to enter your own living room. Odd life you've got there. I recommend improving it with Attack the Block, a witty, slightly scary flick that gets big charm from its small scale.

* Contact Ed Robertson at edwrobertson@gmail.com.