If you don't like cars, I guess all these car games are quite hard to tell apart. If you do, however, you'll know that you're not dealing with a single genre so much as dozens of the things.
All the best games about cars are a little bit different: Burnout is both highly evolved and utterly, utterly depraved, while Ridge Racer is a light-streaked lucid dream where you ghost around corners and send out surprisingly gentle showers of sparks, and Forza Motorsport aims for sheer breadth of simulation options. Gran Turismo? Gran Turismo is part museum and part trip to the dentist: a clinical environment where softly-spoken experts have gathered to venerate and protect anything that comes with a camshaft.
So where does Test Drive fit in? Good question, and it's one that Unlimited 2 seeks to answer in some pretty interesting ways. The first Unlimited was a bit like an MMO and a bit like a summer holiday: a plush ramble (that's possible, right?) around an upmarket Hawaiian island where you took on challenges, launched impromptu rivalries with other players and saved up for weird new motors.
The sequel sticks to the same basic framework but elaborates on the options and player freedom. It also dials up the opulence to the point where the whole thing approaches soap opera levels. Not the grim British soaps which are all about getting your burger van impounded while someone stubs cigarettes out on your arm, mind, but one of those weird, upbeat foreign ones, obsessed with beautiful rich people hanging out on yachts and gesturing with half-filled whisky tumblers as they stand in front of picture windows. The nutty, aspirational ones.
At times, in fact, you may wonder how far the Eden Studios team plans on pushing the concept of simulation. TDU2 takes such delight in the luxurious world it's piecing together that it's happy to let you get out from behind the wheel and leave the car in the garage for long stretches of time should you wish to do so. It's fine - the garages look like mansions anyway, so your cars won't be lonely, and there's plenty of stuff for you to do on two feet as you buy houses, move your furniture about and fiddle with your avatar.
While you may not have signed up to a racing game so you could wrestle with corner sofas and flat-screen tellies, you can't fault the options available. You can tweak every aspect of your avatar's appearance, buy a range of increasingly over-the-top homes, add pictures and manage the stats of your MyLife profile, and invite your online friends over to hang out in your imaginary living room. It's a fascinating prospect, even if many people will stick to simply customising the cars (a wide range of decals and paint-jobs are available), and TDU2's social focus means you won't be mistaking it for any other driving game on the market.
There's a hint of Dead or Alive Beach Volleyball to proceedings occasionally - not in terms of creepy access to some unlikely ladies, but in the way that an aspirational lifestyle has been warped into a charming kind of parody. TDU2 really wants you to explore the world of the rich car enthusiast, and it's a strategy that percolates right down to the point of purchase. Eden doesn't want you buying cars or messing with their engines inside boring menu trees - it wants you to be able to walk into actual showrooms and garages and enjoy the browsing experience in three dimensions.
A lot of this could come off like Home - come to think of it, quite a lot of it could come off like Animal Crossing - but the car culture setting ensures that it feels like a good fit with the rest of the game. Besides, all of the social aspects are tied into the new progression system, where you can move through the narrative not just by racing but also by doing other things like building up your own status.
Avatars come in handy in the seamlessly integrated online options, as you form racing clubs with other players, deck out your clubhouse - okay, I've made it sound like a tree fort, whereas the one I was shown had parquet flooring and up-lighters - and hang around inside it with friends. More importantly, your club can polish its double-dangerous driving skills and take on rival clubs in eight-player races and other challenges.
As a sweetener to getting involved in clubs, Eden's promising treats. There are some very special cars that can only be purchased by clubs, and the whole thing has the chummy air of an MMO guild to it as you approach the 30-person club limit. It's a fitting addition for a game which already feels a bit like an RPG as you tool around an open world, taking on missions and watching your stats go up.
The other means of player progression are far more intimately involved with sitting behind a wheel. You can level up through exploring the game's huge environments and making discoveries (stumble across enough wrecks and you'll be able to bolt together entirely new vehicles), while good old car-collecting ties deeply into the game's preoccupations with luxury and consumption.
Beneath all the new distractions it's worth remembering that this is also a driving game. The good news is it's looking like an excellent one. Eight-player races promise to be punchy and hectic, damage has been included for this instalment - while it won't affect performance, it certainly looks good, ranging from paint scrapes to actual pieces of your car falling off - and car models have been overhauled with far more detailed interiors and a nice new metallic paint effect amongst other tweaks.
Most importantly, the handling has been extensively redesigned to give each car its own personality. It's astonishing the difference this makes: an Audi TT hugs the road with a polite rumbling sound, while a Ford Mustang can be fishtailed all over the shop as its V-8 engine booms. You don't need to be told that one is a classic muscle car and the other is a jumped-up graduation present for the daughters of Tory MPs: just driving them will fill you in about that.
There's definitely no shortage of tracks to drive them on. TDU2 moves the action to Ibiza, a world of palm trees and hi-spec apartment complexes, which has been purposefully riddled with hundreds of miles of roadways for you to blast around. Missions lurk every few metres by the looks of it, and creating your own courses is as easy as pulling up the map and dropping in waypoints. If you come up with a track you're particularly happy with, you can share it very easily, and place wagers on people beating your own completion time.
At 380 square kilometres - and with 930 kilometres of road - there's plenty to explore, and the game is at pains to break up the environments into distinct ecologies ranging from beaches to forests. A new day-and-night cycle is freshly in place and is already bathing the landscape in bleached morning sun one moment, cinematic moonlight the next, while a dynamic weather system means that sudden lightning showers will change the way your car handles as well as adding a bit of drama. Roads are divided between asphalt and off-road tracks, and there's a new class of off-road vehicles to get muddy in.
When you tire of Ibiza - my younger sister did several years ago - you can unlock its airport and blast back to Hawaii where the entire island of Oahu has been retooled from the first game with the new progression system in mind. It's an incredibly generous touch, and there are plenty of new missions waiting for you in the old neighbourhood, threaded alongside hundreds of miles of new roadways.
Eden's referring to its game as a "luxury lifestyle universe", and for once that's a sound bite that fits perfectly. This is something approaching lifestyle software, in the way it grants you virtual access to the kind of world that probably only otherwise exists in some of the limper Puff Daddy videos, in its options to buy not just Ferraris and Mustangs, but yachts and Bauhaus-styled mansions in which to store them.
Gran Turismo may have more cars, but only Test Drive works such a bizarre fantasy around owning them. The result is something that already feels like a true original, and while the social aspects are pleasantly bonkers, the fact that it's all tied into the cars makes it more meaningful. Besides, it's hard to complain when the core of the game has been so confidently improved upon.
Test Drive Unlimited 2 is due out for PC, PS3 and Xbox 360 this autumn.