A singular experience...

Bioshock is a (quite old, in terms of computer games now) videogame. Now, people scoff at games as fun, entertainment or - shock, horror - perhaps something more. But I've just finished playing the demo and my heart is yet to stop pumping.

Bioshock is what's known as a first person shooter, which is nothing special. What is special is the way it works. Firstly, it's more than just guns, guns and more guns. There are sort of super powers known as plasmids which you can use - genetically altering your body in the process. These things mean you can fire electricity from your fist, for example, which is useful in temporarily disabling security cameras, people and - of course, the classic - firing 10,000 volts into a pool of water frying various bad people.

Enough about immature violence. You can get that anywhere these days.

What really makes the game special is the environment. The game starts with a plane crash of which Jack, your character, is the only survivor. Much like Half Life (arguably the best computer game of modern times) you see everything from the eyes of Jack - no movie-style cut scenes. So with a good enough system to run the game on, you see, hear and feel the plane crash. You feel Jack underwater, near drowning, before you take him up to get air. You navigate the burning water to a mysterious looking lighthouse.

This is were the 50s-60s style creepiness really kicks in. The lighthouse contains a bathysphere. Cat like curiousity leads you to step in and be sealed by a fat, pressure-proof door. And you begin your descent down to Rapture. An all too cheerful radio and slideshow begins to tell you about Rapture - the creator and the reason. And suddenly you look outside to see this underwater, art deco City of neon lights. As you get closer, dodging between shoals of fish and blue whales, you can see advertisements on the buildings, gay and kitsch to go along with the broadcast you're watching. The creator of Rapture is speaking (a recording, of course) of why he created Rapture. Freedom, independence, excellence. These are terms that are bandied around liberally through the environments, just adding to the creepiness. Rapture is the epitomy of laissez faire thinking. No petty government interference, which is something you learn the creator - Ryan - has a rather hefty hatred for.

It all sounds a bit strange, but not too bad. As you get closer you hear people talking about your imminent arrival, and - I'll level with you - they're not too positive about your survival. The first thing you see is a bloodied madman with sickles killing someone sent to save you. This guy taunts you for a while, unable to get through the thick glass, and leaves. One of the men from earlier contacts you through a radio you pick up from the sphere, and insists he wants to help you (although by now, you're pretty spooked of everything) and tells you to get to higher ground.

It's only now that you realise Rapture isn't all it was cracked up to be. There are official notices everywhere in the departure lounge informing people that travel has been suspended indefinitely. There are also placards with slogans like 'You don't own us, Rapture!'. The protesters are nowhere to be seen, but - looking around at the debris, cracked glass and corpses - the place has seen better days.

By now, your heart is really having a bit of a time of it's own. The cheerful art deco surroundings are made creepier by the darkness, the screams and mutterings of nearby 'splicers' - like the lovely gent who wanted to kill you earlier in the bathysphere - and your total lack of knowledge.

And from there, it's such a ride (and I've only played the demo! Ha). You inject yourself with something called EVE, which gives you the power to throw aforementioned lightning around - a real help. But when you inject yourself, your head begins to spin and you collapse over a balcony. Vaguely aware, a couple of groups pass your fainted form, debating over grizzly things they can do to you, before deciding you're not worth the trouble.

Your helpful 'friend' contacts you over the radio and directs you to keep moving, and from there is all gets gloriously chaotic. You find a wrench, which is a relatively brutal instrument of defence, and begin the 'Colombo One-Two' - which involves sending a couple of thousand volts through a would-be assailant before beating them senseless. Survival, eh?

I won't bore anyone with the rest of the demo, but suffice to say the environment doesn't stop giving. You sneak through an old dance hall, decorated with 'New Year 1959' posters and complete with creepy, lounge lizard music, trying to avoid getting bludgeoned to death by psychopaths wearing masquerade masks.

It's brutal, it's chaotic and it's terrifying. It elicits all those emotions and more.

Spiderman 3 was beaten at the box office, sort of, by Halo 3. Games are now as much entertainment experiences as movies are. And Bioshock is a perfect example of why.

Download the demo, if your computer will run it. My performance is a bit buggy because I insisted on running it on top spec. Without the eye candy - the posters and neon signs and broken cigarillo machines - it wouldn't be half as fun.