Gran Turismo 5

The moment Gran Turismo 5 clicked for me, I was tackling the tarmac rally stages in Special Events. These point-to-point time trials take place on twisting country roads crossing the rolling landscape of Tuscany.

At the intermediate level in the rallies, the game whipped away my habitual crutch, the racing line guide that traces the best line through every corner. But that wasn't the half of it, because these rally stages are never the same twice. They're procedurally generated by the Course Maker system – one of innumerable gadgets and modes that developer Polyphony Digital has crammed into this bewilderingly eclectic release.

I couldn't even restart and painstakingly learn the track, because it wouldn't be the same track. So I watched the road, listened to the pace notes and felt my Impreza countersteer out of bends and buck over bumps, taking my heart in my mouth with every blind crest.

Suddenly – after two days' play – I wasn't playing a sim racing game any more. I wasn't learning a litany of trackside cues and cornering rhythms I might as well perform with my eyes shut. I was driving with the seat of my pants on the open road, feeling a powerful car under me, mapping the next bend with my intuition.

This is an experience I'd always longed for, something I'd glimpsed parts of in Project Gotham 2's Nordschleife Nürburgring or Test Drive Unlimited's untamed roadmap – but never so vividly, and never with such profoundly realistic handling.

For me, this is the Holy Grail of driving games. And yet it's one throwaway and all-too-brief event tucked away in a corner of Kazunori Yamauchi's sprawling empire of digital motorsport. I could quite easily have played GT5 for dozens of hours and written this review without even knowing it existed.

That, in a nutshell, is everything that's extraordinary and infuriating about this vast, mad, once-in-a-lifetime game.

I don't need to repeat that Gran Turismo 5 has been in development for a long time. What's more important is that it seems to have been developed at this ridiculous length and expense in a vacuum, by a studio pursuing its own unique agenda (I mean, procedurally generated roads?) and ignoring everything that was going on around it.

This, as you might imagine, causes a few problems, such as archaic online multiplayer, an unwieldy interface, terrible optimisation and obtuse structure. But it has its compensations too, not least the fact that Gran Turismo 5 is unlike anything else out there – including Microsoft's Forza Motorsport, a series that was made in its image.

The first impression – at least, after you've recovered from a hilariously self-important intro that sets film footage of steel refineries and car factories to modern classical – is one of familiarity. Here are the glossy, slow menus with their cheesy elevator jazz. Here is Arcade Mode, with two-player split-screen, a selection of cars and almost all the tracks.

Here is GT Mode, where you will scour the used car market for a cheap MX-5 or Civic and drag it round Autumn Ring and Grand Valley, taking the first steps on an epic, RPG-style grind of cashing up, customising, tuning, window-shopping and lapping, and lapping, and lapping some more.

Here are those famous Polyphony graphics, which have somehow kept an unmistakeable house style – a hard, pristine CG look to the cars against grainier, more photographic backdrops – through the generational leaps. They're not perfect. Shadows jitter and crawl, frames drop below 60 per second at busy times, the screen tears, and from some angles at some times the game can look quite plain.

At other angles and times, it's astonishingly real and beautiful, even while it pushes 12 fanatically detailed cars around a busy environment bathed in time-of-day and weather effects that lend an atmosphere so precise and identifiable to the real world, it's eerie. Suzuka's suffused in that fine, mist-like Japanese rain; dusk in Tuscany has a perfect, mellow half-light; Route 5's night-time cityscape surprises with an orchard of cherry trees hung, gratuitously, with fairy lights. It is a spectacle all right, but a spectacle you knew you were getting.