Attack the Block shuffles old standbys -- invaders from the stars, likeable urban ruffians coming-of-age, and the Western/horror/sci-fi assault siege. Director Joe Cornish gives his own script a teen hook with a young cast whose gang leader Moses (John Boyega) replies “Thanks” when white twenty-something Samantha “Sam” Adams (Jodie Whittaker) takes him for older than his mere fifteen years. And also a current relevancy hook in their largely West Indian immigrant background, though, obscene and slangy, the accents are tough for American ears.

Politely ignoring advice from concerned parents, on bicycles, a pizza-delivery scooter or simply “runners” (sneakers), they roam the semi-mean streets around London’s grandiosely named Clayton Estates, specifically their own Wyndham Tower, prettied up from project reality even with its guns and at least one drug dealer (Hi-Hatz, played by Jumayn Hunter) and his underlings. Good kids at heart, Moses, Pest, Biggz, Jerome and Dennis (Alex Esmail, Simon Howard, Leeon Jones, Franz Drameh) are not above street robbery, though when they learn that recent nursing graduate Sam is a first-floor resident they apologize and insist that would not have victimized that neighbor had they known.

What with holiday fireworks, no one notices the bright objects that stream through night skies to crash on English Earth. No one, that is, until one smashes into a car behind these young thieves who have just relieved Sam of a ring and other valuables. (SPOILER ALERT) They chase a stiletto-toothed alien which they kill easily enough and hang up in Hi-Hatz’ climate-controlled marijuana-plant Weed Room. This first dead invader is a female, whose slime on Moses’ clothing acts as a pheromone GPS homing device for the others, males and blind. A couple loom gigantic, but most are adult-chimpanzee-size furballs, “blacker than black, blacker than my cousin,” picked out by Day-Glo fangs, and able to fly or hover but also clamber up hi-rise walls.

Bobbies and SWAT teams oblivious, inept, misguided and absent when really needed, it falls to the five-joined-by-brave-Sam to defend the home turf. They are cheerleadered on by two kids with toy space guns, a gaggle of girl friends -- not yet girlfriends -- and the drug dealer’s comic-relief white front men, portly Ron and lanky teen Brewis (Nick Frost and Luke Treadaway).

Backgrounded by a reggae-rap score and armed with a souvenir samurai sword or two, aluminum baseball bat and assorted fireworks, this neighborhood defense league sets off to do battle with the outsiders. A few of their number picked off along the way, they carry the fight to bloody elevators, interior stairwells and exterior walkways, smoke-obscured hallways, recycling containers and individual flats. Fittingly, these offspring of immigrants arrange Armageddon in the one flat whose balcony conspicuously displays the Union Jack.

Its target audience in mind, the film enters into no potential social side issues. The public housing complex is an unlikely model of care and cleanliness. And any whiff of interracial romance is scuttled by the white heroine’s absent boyfriend doing Red Cross work with youngsters in Ghana -- “Why can’t he help children in Britain?” -- as well as by the age difference between her and the black hero, who lives with an often-absent uncle and sleeps under a Spider Man quilt. When she and rescued neighbors identify him as “a hero . . . a legend,” strong but silent Moses flashes his first and only smile.

Reprising scores of films, despite an unusual combination of story with setting and characters, Attack the Block is unsurprising, adds nothing in the re-doing, sports hokey creature effects, and will probably appeal only to the undemanding.

(Released by Screen Gems; not rated by MPAA.)