If Forza Horizon 2 was a Bestival for cars, all sun-kissed fields and long, breezy summer days, then Storm Island, Playground Games' first downloadable expansion for its Xbox One exclusive, is their Glastonbury; where the mud churns and the rain tumbles down while the wind whistles noisily through the trees.

Price and availability Xbox One: £15.99, or £7.99 for Forza VIP Members

Such extreme elements are all part of the fun, giving this generous extension to arguably the year's best driving game a flavour of its own. How pleasing it is, too, to see an expansion done right so soon after Destiny's The Dark Below got it all so wrong: the price-tag may be significant, but Storm Island is heavy on things to do, with some 80 new events taking in a number of different disciplines and a whole new island to explore.

The island itself isn't really the most striking of backdrops - a thicket of dense countryside and rolling hills that clocks in at just under three miles point to point, aside from a temple atop a hill it's visually indistinct from Horizon 2's landmass - but what it enables helps set it apart. You access Storm Island by departing from Nice's port, and once you've arrived you're met with a whole new weather system that flits dynamically between murky outbursts to syrupy late-evening atmospherics.

Fever! The 6R4, a hero of Rallycross, is met with new events that introduce destructible objects, making for a little more bustle in the action.

Coming so soon after DriveClub's own weather update, it makes for an interesting comparison; Forza Horizon 2's visuals are never quite the measure of Evolution's spectacular achievements, though they do have a more pronounced effect on how the game plays. Thick fog turns off-road duels into Silent Hill-esque horror, where you're never quite sure what's waiting for you beyond that blanket of grey (it's normally a tree, and it's often one with an unhealthy appetite for carbon, steel and rubber.)

Drive by night through a storm in one of the new signature Gauntlets - prolonged events in raid cars that work their way across the terrain - and there's great drama in the manically dancing fauna and the floodlights that mark your course, the reduced visibility accentuating the more slippery handling, those heavy tail-ends wallowing out of place before gently being guided back into step.

Off-road driving featured in Forza Horizon 2, of course, but the fresh emphasis on it here works well, bringing into focus the heritage of developer Playground Games. The Codemasters DNA that showed in the jauntiness of Horizon is more pronounced than ever before, with Storm Island playing out like an open-world Dirt - which turns out to be quite the thing. The cars have the same lightness of touch, the handling both forgiving and satisfying as it once was in Codemasters' best work. It really feels like Forza Horizon 2, in this configuration, owes more to that particular lineage than the one Playground inherited from Turn 10.

The original Horizon played with this heritage in its own expansion, though Storm Island deals with the one criticism of the first game's Rally pack with aplomb. These are no longer events bolted on to the side of the main attraction, and by giving over a dedicated new island they play more to the appeal of Horizon, the rough roads threaded throughout an open world that's free to explore.

It's not all thunderstorms and mayhem - when the sun shines there's room for plenty of beauty in Storm Island.

They're hardly delicate threads, however, and the roads of Storm Island are wild, bucking beasts, featuring obscene cambers and jumps that send you straight up into those threatening skies. You're given the tools to tame them, though; there are new car mods introduced, allowing you to attach rally-specific springs, transmission and tires to any car in your garage (and if you want to make an off-road La Ferrari - you monster - then this has you covered), as well as new off-road specific cars available in Storm Island.

The emphasis is on the big, unwieldy raid machines best suited to the Gauntlets that provide the spine of the championships, but there's some more reserved rides included, too. The Mark 1 Fiesta XR2 makes a welcome, surprising appearance, Tom Tjaarda's diminutive classic available for you to do all sorts of nasty things to, but it's another 80s classic that's the star of the show. Storm Island's sole barn find, a rare classic uncovered by exploring the open world map, isn't exactly refined but the Metro 6R4 is about as stirring as off-roaders get. It's a beast as well, a snarling relic of the Group B era that feels like it's constantly conspiring to kill you as you strong-arm it through Storm Island's countryside.

This is an excellent expansion, then, one that complements the main game while gracefully underlining what exactly it was that made that Forza Horizon 2 so enticing in the first place. The price-tag may seem as steep as one of Storm Island's vertiginous jumps, but if you had any fun with Horizon 2 whatsoever, go with it - it'll send you soaring into another worthwhile playground stuffed with little delights.