"Okay, guys, I have some bad news."

Ken Levine is standing in the functionally palatial Royal Suite at the Beverly Wilshire Hotel. His immaculately groomed appearance and laconic demeanour don't back up the announcement he's just made to the roomful of journalists who are sitting in front of him.

Yet, a small shudder passes through the crowd. The game we're all here to see, BioShock Infinite, hasn't been presented to the press since E3, and even then no one other than Irrational's devs were allowed anywhere near its controls. Since then, the only news that's emerged about the game has centred on the list of high profile departures from the Boston-based developer, leading to speculation that Irrational's latest masterpiece was plunging into development hell.

So what bad news has Levine got on top of that?

"When Rod (Fergusson, Epic's former Production Director) came on the project a couple of months ago - and this dude is living in a hotel nearby because he really wanted to work on Infinite - he really fell in love with the game," Levine says. "But he said, 'look, Ken, I really think the game would benefit from three or four more weeks'."

"I thought ahead to this conversation and went 'Oh God!'," he laughs. "But at the end of the day, we've got to ship a great game. So if it's three or four more weeks, then it's three or four more weeks. So it's March 26th, now."

And there you have it. There's the bad news. BioShock Infinite's street date has been moved to March 2013, delaying its release for a second time.

But here's a question: does that really matter in the grand scheme of things? Ultimately, like Levine says, what matters is whether BioShock Infinite is a great game on release and on the evidence of what I saw this week at BioShock Infinite's first ever hands-on event, neither Irrational, nor the punters eagerly have much to worry about. BioShock Infinite looks absolutely superb.

The game opens in choppy waters off the coast of Maine circa 1912 with its protagonist, ex-Pinkerton Booker DeWitt, sat in a boat under clouds of drizzle as a posh British couple in raincoats row him towards a lighthouse. As the two of them bicker, the female of the pair hands Booker a wooden box with his name in monogram on the lid. Inside, he finds a pistol, some pieces of paper and a couple of colourful flyers. The boat docks on a jetty and the two wait expectantly for Booker to leave and it's here that the player takes control of him.

This is also the juncture at which Infinite begins to transform into a warped reflection of Levine's last game, BioShock. See if this sequence of event strikes you as familiar: the player enters a lighthouse and follows a set of stairs until they reach what looks like a mechanical object they can interface with. Upon activating it, they find themselves in a small, enclosed pod that turns out to be a form of transport. This in turn, takes them to an urban landscape that, while bearing the hallmarks of classical architecture, looks distinctly otherworldly. The pod glides through the towering structures of this zany metropolis and then slowly enters one of the structures, sidling to a halt while passing girders that bear philosophical legends on them. The pod opens, and the player is overwhelmed and immersed in a unique landscape that obliterates nearly every trace of the outside world.

That, in a nutshell is the opening of BioShock. It also, as it happens, is the opening of BioShock Infinite. Naturally, there are differences to the player's entry to Rapture. Some are incidental and for cosmetic effect like, for example, the song playing on a gramophone as Booker enters the lighthouse is from 1910. Some changes seem plot-driven; there's a dead body tied to a chair on the third floor of the building and note pinned to the front door, saying "DeWitt, bring us the girl and wipe away the debt. This is your last chance". And of course, the direction Booker heads in - both in the lighthouse and the flying pod he steps into - is up, rather than down. But heck, the first words directed to the player on their arrival in the floating city of Columbia - Rapture's airborne, sun-dappled twin - by a lay preacher are: "is it someone new?"

The game's mechanics and gameplay will also strike BioShock fans as extremely familiar. Firearms and Plasmids - or Vigors as they're named here - are mapped to the right and left trigger respectively and players switch between weapons and Vigors by tapping the shoulder buttons. Scrounging - for ammo, food, health kits and Salts (which power Vigors) - is the order of the day, and yes, a lot of the game's back story is revealed through audio diaries scattered about the city. There are also robotic vendors players buy ammo, Salts and Vigor augmentations from, and they can pick up body mods that allow them to do things like set enemies on fire or shock them with a melee attack. The major difference in the interface is that there's no button to tap to use a health pack, but this is balanced by the fact that Booker picks up a forcefield early on in the game.

But according to Levine, the mechanic and the visual in-game references are neither the result of Irrational being lazy or unimaginative, nor are they present as a knowing wink to BioShock fans.

"Ah... without getting into spoilers, none of this is an attempt to be cute," says Levine. "Nothing is there just as a nod. It serves that to a purpose - I mean, if you're a BioShock gamer you'll obviously notice a line here or a visual reference there. But, it's really hard for me to talk in depth about that without spoiling a lot of things."

"I can't wait for gamers to finish Infinite," he says. "It'll be interesting what they think of the game's themes and how they evolve."

Booker has quite a few more abilities in Columbia than Jack had access to back in Rapture. For a start, each Vigor has a dual effect; click the left trigger quickly and Booker launches a distance attack with it, but hold down the trigger and then release it and Booker plants a trap in the floor. So, for example, if the player has Devil's Kiss armed, a quick fire attack launches a molten grenade that sets any targets in its vicinity on fire, and a trap attack plants a trip-mine in the floor that incinerates any enemy that steps on it. A lot of the Vigors, however, seem like better developed versions of the Plasmids found in Rapture - for Devil's Kiss, read: Incinerate, for Shock Jockey, read: Electro Bolt. Even Murder Of Crows, in effect, is a version of Insect Swarm and Possession combines the effects of the Security Command and Enrage Plasmids.

Still, BioShock Infinite puts a premium on players using their immediate surroundings and the contents thereof more than BioShock ever did. Players are encouraged to scout around in their environment to find the optimum point in the map to wage a battle, depending on what weapons they have and what Vigors they prefer to use. Shotgun jockeys may prefer, for example, to head into a tight corridor and load up the floor with traps either side of them. Players who use precision weapons - sniper rifles or handguns - may want to possess a couple of enemies and turret and then pick off targets as their enemies turn on each other. Irrational's new game is a corridor shooter, sure, but it's an awfully wide corridor. On Easy setting, using Booker's environment is optional, but on Hard, it becomes essential to his survival.

The addition of overhead rails - and Booker's Skyhook - adds another element to the combat. Players use this magnetised tool to hang from hooks or latch onto rails that can send them hurtling alongside targets, flanking them out of cover. Thanks to the well-designed controls, it's a synch to lock onto targets - although Vigors are taken out of the equation - and players can also use a dismount kick to send an enemy flying off one of Columbia's raised platforms. The Skyhook is also a particularly nasty melee weapon - especially if players hold down the Y button, which causes Booker to push it into the face of whatever enemy he's facing and turn it on.

Then there are the 'tear' mechanics, which come into play when Booker meets up with Elizabeth. At certain points in the environment, players will encounter sections hovering in the air which blur the visuals around them. If they focus on these 'tears' items such as gun turrets, weapon racks and ammo dumps will swim into focus, overlaid with static affect denoting that they currently exist in another dimension. Players can then tap the X button and have Elizabeth pull them through into the material world.

Ah, Elizabeth, the focus of Booker's efforts and the brand new mechanic for BioShock Infinite. She's changed somewhat visually since the first time gamers were introduced to her; her plunging neckline and heaving cleavage have been tastefully covered by a blouse and neck scarf. She's also something of a boon to players as they plough through Columbia's forces in an attempt to get her off the floating city and back to civilisation. Players don't need to worry about keeping her alive in a firefight as she'll take cover immediately. She'll also scrounge up weapons, ammo and cash while they're kept busy with slotting targets. Her overriding use, though, is wrapped up in her trans-dimensional powers, which as has been mentioned, can teleport useful equipment from other planes of being.

As for her contribution to the plot... well, now once again, we're skirting the edge of spoiler territory. The less players know about Infinite going in, the better - to be honest, I feel more than a tad guilty about revealing the game's opening moments, but this is a preview and what can you do? Levine, quite rightly won't be drawn on any plot revelations.

He will, however, talk about the media speculation that erupted earlier this year when news of the departures of key staff members broke earlier this year.

"I wish there was an exciting, dramatic story to tell here. Look, you've worked at a company - I'm sure you've seen people come and go. For some reason [the departures] got a lot of publicity and I think that a lot of that had to do with the fact that there'd not been much news about the game - we'd kind of gone dark. I think that made people worried and made them speculate."

Still, you'd have to admit, it wasn't like the fans and media were spitballing in a vacuum. Between August and October, BioShock Infinite's Art Director, Product Director, AI Lead and Combat Design Director all trooped out the door and then it was announced the multiplayer mode may have been removed from the game altogether. It was also round about that time that Rod Fergusson joined the project and, rightly or wrongly, he was seen as a steadying factor.

But Levine is of the view that the departures from Irrational weren't the high drama they were made out to be, although he admits that the fact they were the only news Infinite's audience was getting, didn't help much.

"It's like [our audience] looked at us and went, 'are they hiding something?'," he smiles, "but it's like I told the team: 'look, guys, you're gonna see these stories, they're going to make you feel bad and then you're gonna move on because ultimately, you'll put a controller into the hands of your audience and then they'll tell us the state of the game'."

And as has been said, the state of the game looks marvellous. Strip away the familiar and look past even the new mechanics and there's something extraordinarily special occurring in BioShock Infinite, which, without giving too much away, players will spot if they pay attention to seemingly incidental occurrences in Columbia's environment. The game throws up questions on an almost minute-to-minute basis.

Why, for example, does Booker have flashbacks to an office where someone is hammering on his door about an unpaid debt? Why is a beachfront band in Columbia playing a cover of Cyndi Lauper's Girls Just Wanna Have Fun? Why do the posh British couple from the boat continue to pop up at intervals in Columbia after they dropped Booker at the lighthouse dock - and why can no one else see them? Why does Elizabeth seem so shocked at the religious zealotry and racism that is par for the course in Columbia's 1912 society?

I feel I've said too much by even raising these points. After five hours at Infinite's controls, though, the overriding memory I have - aside from the game's gorgeous, yet barmy, steampunk city - is of Ken Levine speaking to me with a twinkle in his eye and the hint of a smile playing on his lips.

"None of this is an attempt to be cute. Nothing is there just as a nod."

Players may be in for an immersive experience by booking passage to Columbia, but BioShock Infinite - if I'm reading this right - promises to be a head trip of epic proportions.

BioShock Infinite is due for release on Xbox 360, PS3, and PC on March 26.

This preview is based on 5 hours with BioShock Infinite's campaign mode. The preview event took place in Los Angeles. Flights, food and accommodation was paid for by 2K.