Every now and then, Hollywood has a spasm and churns out pairs of movies about the same thing. Giant space rocks provided the drama for both Deep Impact and Armageddon. Lava threatened famous faces in Dante's Peak and Volcano. Magicians got all huffy in The Illusionist and The Prestige.

Gaming experienced its own version of this phenomenon in 2009, when both Sony's inFamous and Activision's Prototype posed the important question: what would happen if an obnoxious wanker got superpowers? With Prototype 2 still conspicuous by its absence, only inFamous star Cole McGrath may be around to answer that question a second time.

Picking up almost directly after the first game, inFamous 2 opens with Cole tackling The Beast, the mythical destructive monster teased throughout the original adventure. Cole promptly gets his butt kicked. He retreats to the city of New Marais to recharge his electrical superpowers and prepare for round two.

It's a change in location that benefits inFamous 2, as is obvious as soon as we're seated in front of it at Sony's PlayStation Experience. While the urban cityscapes of the first game were an easy fit with the superhero genre, they were also fairly generic and hardly inspiring.

New Marais, based heavily on New Orleans, is a much more interesting place to explore, with unique architecture and an old world charm that makes the lightning-bolt mayhem stand out all the more.

But we're not here to explore the scenery - we're here to see how Sucker Punch has revamped the karma system from the previous game. The stated aim is to present the player with conflicting characters, each representing a different approach to a mission. To illustrate the idea, we get to play through an early mission both ways.

At the start, we're on a rooftop with two support characters. Our task is to free Special Agent Kuo from captivity, as she is apparently able to help evolve Cole's powers to Beast-defeating levels. Our companions have a difference of opinion over how best to proceed, though.

Zeke, our old pal from the first game, favours a more inclusive approach. The city's cops have been rounded up by the local crimelord and are being transported across the city in an armoured convoy. Free the cops, suggests Zeke, and they'll help you to storm the stockade where Kuo is being held.

Nix wants no such soft-touch nonsense. Her recommendation is to hijack a tram car, load it with explosives, supercharge it with your electrical powers and smash it through the front gates. Messy, but direct. Your choice made, it's off to the relevant mission marker to get the job done.

It soon becomes clear that the different approaches don't really manifest as different gameplay experiences. It's possible to cause just as much mayhem while freeing the cops, and both routes boil down to a lot of climbing on top of moving vehicles and blasting hordes of enemies.

That's certainly satisfying, but negotiating the tangle of New Marais streets and getting on top of your targets isn't as smooth as it could be. Cole's movements feel distractingly stiff, especially when the game decides to glue him to precarious perches.

I repeatedly found myself surfing on overhead wires whenever I tried to jump on top of the tram car, while rooftop parkour feels bogged down by this stickiness. There's no doubt that, were the wires where I wanted to be, I'd be glad of the assist in staying balanced. Since they weren't, I couldn't help making mental comparisons to the effortless navigation of Assassin's Creed.

Once inside the enemy compound, by either method, there's more mild disappointment when it becomes clear that which ever character you side with, the game plays out exactly the same once you've breached the gates. Enemies spawn in the same locations, gameplay events trigger at the same time – the only difference seems to be the character running around nearby.

This is balanced out by the fairly radical overhaul dished out to the game's melee combat. Never the strongest part of the first game, it's one of the most polished and enjoyable aspects of what's on display for inFamous 2.

Combos are simple but satisfying, and it's much easier to mix and match old fashioned punches and kicks with your crackling electrical powers. Softening up a thug with a flurry of punches then booting him into the air with a fizz of static is instantly gratifying, all the moreso as chains of successful attacks fill your power bar and allow you to let fly with a very impressive lightning-fuelled tornado which whips through the scenery, dragging friend and foe alike into the sky.

Of course, it's always hard to make assumptions about the shape of an entire game from a ten minute sequence, but on this admittedly slim evidence the much-vaunted karma system is hardly looking revolutionary.

The good news is that the moment-to-moment combat has been beefed up and, if Sucker Punch can smooth out the movement control a little, inFamous 2 is shaping up as another solid open-world action experience.