As the old saying goes, "If it ain't broke, don't fix it." In the case of Borderlands 2, most people would be satisfied if Gearbox followed the idiom and gave us more of the same loot-n-guns action we enjoyed back in 2009. On the face of the game's first showing, however, it seems as if the developers are aiming to up the ante.

That's not to say this sequel is a massive departure; the cel-shaded look is as distinctive as ever, while the anarchic chaos that unfolds before our eyes offers immediate proof that the game's tone remains gleefully mischievous. Under the hood however, it's clear that there have been several revisions to the core mechanics, the results of Gearbox's self-proclaimed intention to "Gut, replace or revamp" its own successful formula.

Let's start with the guns. There are still thousands of them, but this time the differences between manufacturers will be more pronounced, to the extent that you'll instantly know who made a given weapon on the basis of the way it looks; beyond this, you'll also know what to expect when you first pull the trigger. Vladof guns have an AK47-style Russian aesthetic and all come with gatling barrels, their rate of fire accelerating from a slow rattle to a fearsome hailstorm of hot lead. Tediore, dubbed by Gearbox as "the Walmart of guns", offer disposable firearms that you throw away rather than reload: the weapon effectively becomes a grenade, with the strength and effect of the explosion depending on how much ammo was left in the clip. Torgue guns appear to exclusively fire explosive projectiles, while the new Bandit-class arms offer massive clips and a junkyard, cobbled-together look.

As we already know from the first teaser image, Borderlands 2 will also offer us a new set of character classes in place of the original quartet. One of these newcomers will be another Siren - this one's called Maya - but unlike Lilith, her power doesn't involve phasewalking. For the time being, Gearbox is only talking about Salvador, the Gunzerker, and even then we've only been given a brief glimpse of his potential. As an evolution of Brick the Beserker, Salvador's class skill revolves around dual-wielding - a talent that looks to be just as devastating as you'd imagine. Expect this skill to go hand-in-hand with the accentuated differences between gun types.

We didn't get much opportunity to inspect Salvador's skill tree, but it seems that there will be more abilities to choose from this time. Each subset of perks now gets its own Y-shaped tree, with what looked to be about a dozen options on each - I didn't get time to count. Sal's skills include Die Hard, an old favourite of Brick's, plus Asbestos (which reduces negative status effects) and the excellent-sounding Just Got Real, which increases damage done with all weapons. I'm pretty sure that's what they do, anyway: I had only seconds to note down the options as the demonstrator flitted past them.