Long read: The beauty and drama of video games and their clouds

"It's a little bit hard to work out without knowing the altitude of that dragon..."

If you click on a link and make a purchase we may receive a small commission. Read our editorial policy.

Driver: San Francisco

Coma police.

When people associated with long-running video game series tell you, "We've made some real changes this time around," they generally mean that they've added a crouch button. When one of the Ubisoft Reflections team said that to me last year, however, they really weren't kidding.

Driver: San Francisco returns to the open road with a new and refreshingly weird central mechanic. For this instalment, super-cop Tanner's in a coma, and the entire game is his fantasy – a fantasy in which he can leave his body, float through the air like a paper bag blowing on the wind, and possess any passing car he chooses (again, just like a paper bag).

They've, you know, made some changes.

Last year we discovered that, in terms of multiplayer, this makes for hectic, sometimes pleasantly confusing, fun: a gear-grinding battle-racer with a back-and-forth pace that marks it out from any other driving game.

Now, with the September release approaching, Ubisoft is revealing what Tanner's medical problems mean for the single-player campaign – and it's surprisingly slick stuff.

The new game picks up where DRIV3R left off, with Tanner's archrival Jericho about to be sentenced to life imprisonment. Despite the thudding trance bass, the opening cinematic manages to capture a real sense of seventies chase movies as it zips around the streets of San Francisco, switching in and out of split-screen while it details the villain's ingenious escape, involving an acid pill and a rocket launcher. (History records that Martha Stewart busted out of jail in much the same way.)

Jericho and Tanner may be the leads, but the game's steadily introducing the real star of the show every time the camera swoops down an alleyway or zips around a hairpin. San Francisco's not a hugely detailed place by Liberty City standards, perhaps, but as soon as you're allowed to get behind the wheel of Tanner's Challenger, it's clear that it's a lovely playground, both airy and intricate.

The sun's shining, there's a natural mixture of great straights and panicky corners, and cars have a genuine sense of connection to the road. The whole thing purrs along at 60 fps, too. Nice work!

Pretty soon, we're squealing through downtown traffic in pursuit of an armoured car with Jericho at the wheel. Threading through the oncoming lane's a responsive joy in Tanner's Dodge, and there's just enough time to run through some pedestrians to see how they scatter – pretty convincingly – and plough into a VW Beetle – just because it's a VW Beetle – before things start to get serious.

The Challenger's handbrake turn into a tight alleyway, trash flying and tyres wailing, is as good a signature move as some games ever get. Driver nails the moment beautifully, but San Francisco's true defining idea is just about to be introduced, after a head-on collision sees Tanner waking up – or at least thinking he's waking up – to discover he's emerged from the crash with the unlikely ability to leap out of his body and into the souls of other drivers.

And so one tap of a face button sends you into shift mode, pulling the camera up out of your car, and allowing you to float over the streets of the city. You'll be able to upgrade shift powers over time, lofting you higher and higher into the sky, but even at an early stage you can twin-stick your way around a decent chunk of real estate, hovering over cars to see a breakdown of their basic stats, before diving into them.

Whenever Tanner shifts into somebody else's body, players will still see Tanner, while any NPCs travelling with him will see the person he's inhabiting, Quantum Leap-style. In-car conversations are delivered via nicely animated picture-in-picture moments, and Ubisoft's busy filling the traffic jams of San Francisco with interesting characters to drop in on.

The game's first mission, for example, sends you into the body of an ambulance driver, and sees Tanner unwittingly responding to his own RTA. It's potentially rather confusing, but the emphasis isn't on your super-cop's metaphysical bewilderment so much as getting a sense of how nuanced the steering models are in this game.