Even so, it's all surprisingly easy to get into. GT's infamous licence tests are absent, but beginners can call upon steering and stability management to correct oversteer and avoid skids, while the driving line shows you where to go and where to brake. Braking target-speeds hover above corners, so if you keep half an eye on the speedometer you can see exactly when to reapply acceleration, and there's no penalty for using these crutches throughout the game, while the volume of cars beyond your means on the first play-through and the fearsome challenge of the S-Class races encourage you to kick off the stabilisers once you're suitably adjusted.
GT bills itself as "The Real Driving Simulator". There's depth here thanks to a choice of Standard and Professional driving physics, emphasising the already stark differences between the various cars. As well as choosing between three types of normal, racing and sports tyres, as you could in HD Concept, you can now choose different sets for front and rear. The Quick Tune page is host to countless sliders, drop-downs, and graphs plotting torque, power and gear ratios. Cars are tangibly beholden to what's been set for them, and audio cues assist with slipstreaming, while the track surface is manicured subtly enough that you can feel the difference in key areas. Vibration will help here, when DualShock3 eventually materialises in the West, and Prologue's ready for it.
The game's interface is no less slick. Everything is accessed through My Page, a glossy preview of your currently-selected car in quiet surroundings, like a crumbly stone-walled garden in Nurburg, where your car nests in thick grass and butterflies dance in the sunlight, or a quiet-looking Kyoto suburb or a park in Bad Neuenahr. Icons run across the bottom of the screen, and as long as you're connected to PSN a calendar sits on the left beneath a compressed world map dotted with race locations, each one throbbing slightly as a rotation of real-time weather readouts for each area refreshes in the top-right. From My Page you can access racing news (sadly not active pre-release) and download high-definition videos from Gran Turismo TV. These include historical videos (and, if you bought the PSN version rather than Blu-ray, downloadable versions of the opening and closing movies), and Top Gear episodes are meant to follow thanks to a deal with the BBC.
Another icon of which you'll be taking note is "Online", the doorway to Prologue's vaunted 16-player online races, but this is easily the weakest part of the game in its current state. With no in-game XMB (summer, hopefully) and no bespoke friends lists or proper matchmaking options, you just pick one of the server-set tasks and wait for the game to link you up with other players. Pre-release, these were placeholder tasks like a single-lap, all-comers race around a particular circuit, and an online time trial with its own leaderboard. Next to the vast array of options and brilliant Xbox Live integration in games like Forza Motorsport 2 and Project Gotham Racing 4 on 360, it's incredibly basic, although Polyphony plans to add more functionality later. As long as the range of tasks is refreshed regularly, it should offer a lot of gameplay, and performance was solid in our tests, but keeping the specifications out of your hands is completely at odds with the rest of the game.
And while the interface is certainly arresting, it's a little unintuitive in places. Events and split-screen races allow you to restart the same race or boot you back to My Page; there's no quick and simple way to switch between cars without entering the Garage via My Page (irritating when you'd rather just move onto the next task in sequence with a suitable car); and while the range of adjustable game options is vast, they are only accessible, again, via My Page, and not during races, where adjusting button layouts and audio levels is most practical and desirable. There's no option to customise the music you hear, either, and single songs repeat themselves during events that exceed their runtime, rather than cycling to the next.
Gran Turismo 5 Prologue is cluttered with minor imperfections and imbalances such as these. Event mode takes longer to finish than many of the PS3's big-name action games, and Quick Tune extends its life considerably, but it's not brilliantly structured. Drift Trials are separate, racing penalties are ignored until S-Class and Manufacturer races. The gorgeous London track is barely used unless you go after it. Prologue's definitely not just a demo, but it's not quite a game, either - it's more of a play-set for petrolheads, declining to impress more than a tokenistic difficulty curve upon you and letting you tinker and challenge yourself instead. As a result it's not quite brilliant, and we particularly mourn the apparently stillborn online racing, but there's more than enough here to justify the asking price, and exploring it all is a consistently pleasurable experience, which should have considerable appeal for GT's ardent supporters and satisfy the curiosity of the rapidly-growing PS3 installed base at the same time.
Gran Turismo 5 Prologue is due out on PSN on 27th March and Blu-ray at retail on 28th March.