Perhaps one of the most eagerly awaited titles on display at last week's E3 event was to be found lurking behind closed doors at 2K Games booth. Dubbed the spiritual successor to System Shock 2, a series that is unlikely to ever see another instalment due to the complicated legal situation surrounding the rights, Irrational Games and 2K Games, Bioshock, already has a lot of expectations placed on top of it despite the fact that there's more than one year left of development.

With initial concepts and designs allegedly beginning in 2004, it wasn't until 2K's acquisition of Irrational Games earlier this year that the game was formerly announced. The demonstration taking place at E3'06 was handled by Irrational's Art Director Nate Wells and Lead Animator Shawn Robertson.

Intriguingly both Irrational and 2K are being coy on the details behind Bioshock, and rather then just for marketing purposes, these secrecy appears to be a key aspect of the game, with a genuine mystery that unravels throughout the game. What we do know is that the game begins abruptly with the player discovering an underwater facility that was constructed towards the end of WWII in 1945, by a billionaire idealist who grew paranoid that the world would be coming to an end. Scouring the world for the best artists, the best musicians, the best economists, the unnamed billionaire succeeded in luring them to "Rapture" and creating an opulent society underneath the surface of the ocean, with all of the luxuries brought down from above. Beginning the game, the only piece of information presented to you is that something happened on New Year's Eve in 1959; you're not sure what date it is at present, you're unaware of exactly what's happened, you don't even know who you are!

Rapture is (or probably was) a magnificent place to be, marble proliferates the dwelling, fine paintings hang from the walls and grand pianos decorate rooms. Unfortunately it seems not as much attention was paid to the engineering of the structure, with water from the ocean outside seeping through and slowly bringing the once luxurious location into a state of disarray. This notion has been brought to life with stunning effect by the team of artists at Irrational, there's such a distinctive contrast between the opulence and the slow decay that is occurring, whilst a dedicated artists and animator is currently spending every day on the water effects, which certainly shows even at this early stage in development.

The demonstration properly got underway with the appearance of a "Big Daddy" character, one that has become synonymous with the game through the early artwork and screens that have emerged. Looking like something that has stepped out of a Jules Verne novel, the Big Daddy's role is one of a protector who must escort a little girl named "Little Sister" in the scavenge for Adam - the game's sole resource. The Big Daddy/Little Sister pairing scout around Rapture in an attempt to locate corpses and harvest their Adam; the AI behind the game handles such NPC characters, who will dynamically go about their business throughout the game, only becoming interested in the player if he steps too close and causes Little Sister to panic and putting Big Daddy into defence mode.

Amidst the desolation and disappearance of everybody on Rapture, somehow violence has escalated and the protagonist quickly finds himself under attack; however this isn't an ordinary armoury offensive. The residents of Rapture never considered that things could go wrong on the sub-aquatic facility, so never took munitions with them. Thus the game is littered with DIY weapons such as a turret-gun improvised from a swivelling office chair with a motor attached to it, along with a camera and a hastily made machine-gun of sorts.

Embellishing the heavy RPG undertones of the game, and suggesting a similar implementation to the nano-augmentations featured in Deus Ex, Bioshock features several different Plasmids to initialise and enhance certain abilities such as steadying your hand whilst aiming, being able to manipulate machines or activate a boost to your speed amongst many others. Such abilities are grouped into three different categories: Physical, Engineering and Weapons, and much like Deus Ex before it, it's these aspects that open up the world of Bioshock to multiple solutions dependant on the player's choice.

The key issue behind Bioshock is one of "player choice", it's a concept that has been prevalent throughout Irrational's titles and stems back to their days at Looking Glass Studios, working on titles such as the aforementioned System Shock and the equally legendary Thief series. It's a policy that has influenced many of those that were grouped together at the time, with the same ideology evident throughout Warren Spector's Deus Ex series.

Coming from the creators of System Shock 2, by and large, scaring the player is also a key component behind the game, though not in the conventional throw things at you from a dark corridor, but more in a psychological, make you feel uneasy, kind of way.

Despite Bioshock taking place in a fully recreated world, which players are free to explore and interact with, items, ammo and other such objects are hard to come by throughout the game, which emphasis the feeling of having to scavenge through a decaying world and finding solutions to meet the problems presented to you. One example during the demonstration was utilising armour-piercing bullets against a turret, however Irrational are keen to point out that all types of vulnerabilities will be evident in the game: heat, cold, disease, poison, etc...

So far the experience in Rapture seemed to be quite agreeable, with the only conflict occurring when you step on the toes of Big Daddy and get too close to a Little Sister. All of this changed however when a Splicer entered the scene; a former resident of Rapture, who much like the main character is starting to restore themselves using Plasmids in an attempt to enforce their vague memories of who they actually are.