Sitting down at the Borderlands 2 machine at Rezzed, I felt instantly at home. Borderlands was a winning formula, the satisfying cooperative gunplay and the Diablo-like loot collection getting along like a house on fire – a house made of TNT, big guns, and insane psycho gnomes – and Gearbox have made sure not to stray too far. Even on a controller, the weighty weaponry, colourful aesthetic and general mayhem make the sequel instantly recognisable.

For those worrying, don’t – keyboard and mouse apparently works just fine, as I was assured by an apologetic attendant, it’s just that reloading makes the game explode. Let’s hope that one is fixed before launch. PC gaming, ey?

I was playing as Zer0, the cybernetically enhanced ninja – one of the four new classes replacing the originals – and once again, Gearbox have refined what was already wonderful in the original opus. The skill tree is focused around a core skill, but still offers three distinct routes to progress along – in Zer0’s case, a sniping tree, an assassination tree, or a decoy tree, all three of which take advantage of his key skill: enabling his cloaking device to vanish into thin air, leaving only a virtual decoy and some disappointed enemies in his wake. It’s slick and satisfying, managing to make you feel both totally overpowered when you pull off a good assassination, yet terribly fragile when it all goes wrong and you uncloak surrounded by gun toting soldiers and out of cover. It’s similar to the Siren’s cloaking ability from the original, but more physical and satisfying – the Siren’s attacked from stealth with a magic submachine gun, zer0 attacks with a robot laser sword. That’s pretty damn awesome.

The other characters seem similarly thought through: the Gunzerker can dual wield any two weapons (and yes, that does include dual rocket launchers, which is so insanely ridiculous it can only be good), the new siren can levitate, then crush enemies with her mysterious psychic gifts, and the new and enhanced soldier can now drop multiple turrets. This is Borderlands all over again, turned up to 11.

It’s not all familiar though. Gone are the wild wastes of the original Pandora: at least in the demo I played, Pandora has been reclaimed, a gleaming city of glass and steel built in the sprawling deserts, ruled over by Handsome Jack – the tyrannical, and yet surprisingly un-British, CEO of gun maker Hyperion and self-proclaimed dictator of Pandora. Your priority this time isn’t the mythical vault or the endless treasure it doesn’t actually contain, but to kill Jack and end his tyrannic rule.

Borderlands 2 takes place five years after the original, and from the screenshots we’ve seen and my time playing the game, Pandora has changed a lot. You’ll now fight across not only vast cities, but also arctic wastes and whatever deserts remain on the planet. The slightly one-dimensional colour palette of Borderlands’ environments was one of my main criticisms of the game, and it looks like Gearbox have no intention of it letting it go unheeded into the sequel.

The other was the enemies. Borderlands had you facing off against bandits, soldiers, and skags – my god, so many skags – in an assortment of different technicolour shapes and sizes, but that was mostly it. They had AI that was intelligent in the same way as my TI-89 is “scientific” – they’d generally run towards you like bizarrely resilient zombies, helpfully popping out of cover at random to let you grab that all powerful headshot. In the half hour I played of Borderlands 2, that seems to all have gone out of the window. The gleaming silver city was packed full of gigantic robotic constructors, as well as their automated repair drones, an army of battle droids, and then some good, old fashioned soldiers to top it all off. I didn’t have a chance to see just how much the AI had changed, but it looks like Gearbox have at least grasped the crux of the problem – whereas Borderlands foes were mostly identikit foes forced into different shapes and sizes, enemies here act, react, and fight differently.

There is so much more I could talk about here – the new guns, the new NPCs, the new vehicles – but I worry I’m straying from journalistic praise into rampant fanboyism, so I’d probably best stop. What matters is that, from what I’ve seen, Borderlands 2 is really, really good. It’s taken a great game, fixed what was most wrong with it, and served it back to us on as silver platter, topped with personality, humour, and enough guns to take humankind back to the stone age. Pandora is oh-so-familiar, and yet completely different, and that’s exactly what I wanted. I can’t wait to go back.

Borderlands 2 is set to hit PC, PS3 and Xbox 360 on September 18 across North America and on September 21 across Europe. Check out the game’s latest trailer below.