District 9

Alien skirmishes. Big guns. Badass military hardware. Interstellar war. Yeah, the Halo movie would have been pretty cool. Alas, with credit being crunched at every corner, a $200m budget was deemed too expensive for a mere videogame movie (but a toy movie? Well, that's another story) and the project was canned. Bummer.

Or not. From the charred ashes of the proposed Halo movie comes District 9, an action sci-fi that doesn't boast an in-built audience of 27 million gamers, but has that most underused and effective cinematic weapon: the element of surprise. Face-palmingly original, frequently jaw-dropping and boasting stunning visuals that betray its $30m price tag, District 9 is the cast-iron sleeper hit of the summer. After 112 of the most pulse-quickening minutes of the year, you won't give a single solitary shit about Master Chief.

The concept dares go beyond the bog standard invasion template and wonders: what happens if the aliens don't want to kill us or warn us of impending doom, but just want a place to crash? Set in Johannesburg, South Africa and adapted from former commercial director Neill Blomkamp's short film Alive In Joburg, District 9 has a fairly blunt allegory for apartheid at its core but builds from it a genuinely thrilling alien invasion movie that feels like nothing you've ever seen before.

[gallery]The extra-terrestrials here are neither terrifying or cute 'n' cuddly - they're a problem that humanity wishes they could sweep under the carpet. Nicknamed "prawns" by Joburg locals who are sick of the money spent on keeping them around, the inhabitants of dusty slum District 9 came to Earth in search of refuge but found only indifference and veiled hostility. Inept government suit Wikus Van De Merwe (Copley) is tasked with rounding up the illegal aliens and shepherding them to smaller confines. His job is not easy.

District 9 is a mulch of different ideas and devices. The first half hour is shot in a cinema verite style, posing as a documentary on later events and acting as an excellent introduction to the universe Blomkamp and producer Peter Jackson have created. Later, when the action ramps up, the handheld style is ditched for optimum effect, streamlining the concept into a cutting-edge sci-fi. The transitions are noticeable but, thankfully, the story grips from minute one. Like Cloverfield, District 9 takes a tired old genre and revitalises it by looking at it through fresh eyes.

The setting of Johannesburg is the key: it transports the alien invasion template a whole world away. The rusty old South African crap-shacks of District 9 - all actual Joburg slums - play perfect host to the sympathetic first half, in which the script has you rooting for the oppressed aliens, as well as the action-packed second half, where they mount their fightback. South Africa is a breathtaking locale; sometimes it pays to remind Hollywood that New York and LA aren't the only places on Earth.

Nestled under Peter Jackson's wing and with WETA's VFX at hand, Joburg native Blomkamp has a healthy cinematic arsenal at his disposal. District 9's action sequences - including one insane 30-minute fire-fight that closes the movie - pack an audible thump. For all of Terminator Salvation's iconic imagery and Transformers 2's gusto, these are the most intense set-pieces of the year. Wikus' mission to retrieve an alien canister from his heavily-armed government headquarters ranks up there with Terminator 2 in the 'building assault against impossible odds' stakes. Seriously. Goosebumps. Cameron would be proud.

Halo might be a distant memory, but there are definite videogame vapour trails visible in District 9's DNA too. In particular, gamers will enjoy the alien weaponry (including variations on Quake's lightning gun and Half-Life 2's gravity gun) and the final reel's ridiculously cool robotic exo-suit, which could have stomped its way on screen straight from Metal Gear Solid. When enemies simply explode in a shower of guts upon impact, you half expect a high score to flash on screen.

Yet District 9 is never empty spectacle. Newcomer Sharlto Copley anchors the movie with a mostly ad-libbed, layered performance that shows humanity at its best and worst - remarkable, when you consider Copley has never acted in his life and only starred as a favour to Blomkamp. He injects a rich vein of dark humour into proceedings too, thanks mostly to his near-constant cursing, peppering the script with an endless stream of 'Fock's like a Montana family piss-up.

Copley's searing performance is complimented by the fact that the aliens themselves have genuine screen presence: WETA's effects are getting closer to photo-real by the day. It's no spoiler to say you're asked to sympathise with the prawns, but you may be surprised how much emoting a CG critter can do - that's testament to the talent involved. You'll reach a point where you realise you've made an emotional connection with a collection of pixels - but tellingly, only after the pulse has slowed and the movie has finished.

This is a film that will linger long in the memory - it is destined to be a classic. With an untapped director at his rawest, a sage producer at his wisest, an effects house on top of their game and an original, yet-to-be bastardised concept that delivers, District 9 is that perfect animal: an all-compassing event movie without the hype. Smart, funny, touching, thought-provoking and utterly insane in the action department, District 9 is 2009's most entertaining movie by a light year.

Now, can you really imagine anyone saying that about Halo: The Movie?