The Good and the Bad.
Graphics: 10/10
Assuming you've the nuts to play this game at it's highest graphics settings, you'll agree with me. The cars, as is the benchmark now, look almost real-life. The surroundings is absolutely amazing, with some areas on coastlines, some on beaches, some in mountainous forests, and others in the urban jungle. You cannot ask for more in a racing sim. The lighting is especially astounding, with it's blinding effect when you suddenly face the sun that gradually fades away and shadow effects. Also, the GPS is surprisingly detailed; at it's highest zoom, you could even see cruise ships actually coasting by the shoreline and ant-like vehicles scurrying around the map. At it's lowest zoom, you see the entire island laid out as it is seen in reality, complete with cities, beaches, and ports at the correct locations. Finally, the driver's seat view is immensely detailed. Everything in a real car is found on the dashboard, including even A/C buttons, CD Player, etc. The feature that allows you to choose different colour combinations for the interior designs also makes the cars feel so much more like your own real-life car.
About the only negative in graphics is the hardware needed to run this baby. You'll need around 2 Gig RAM, 256mb Video card, and a 3 Ghz or equivalent CPU for the game to run at a smooth pace, and that's at medium settings too. I've also heard of problems when attempting to play with an inferior card. But these problems are small considering the graphic-dreamland that Test Drive Unlimited provides you.
Sound: 9/10
Good, unique sounds for each car that are suited to the vehicle in reality. I don't know what a Ferrari sounds like, but the Mercedes and Nissans sure sound like the real thing. One feature that stood out to me was that the engine noises and other respective sounds were noticeably dampened when you close the windows. That small difference may seem insignificant, but it definitely shows the attention to detail that Atari put into creating this game.
Gameplay: 9/10
Storyline - Here's the bad first.
Would you be surprised, but this game HAS no storyline. If it weren't for this game's other spectacular pros, it would fail miserably in this department. The races get very repetitive sooner or later, since the AI is quite stupid. I'll elaborate. On straightaways, (such as highways) the AI could somehow keep blazing along at 300+ km/h (near max speed) without hardly wiping out once in 5 minutes. To prove it, simply race the "Tour the Island" 189 km race and you'll see what I mean. However, on corners and such, the AI has to inexplicably slow down to 50 km/h to take them. This makes for truly boring races because on straights, you'll most likely be far behind the pack, then on corners, you'll smash into the solid metal wall in front of you that's slowed down to 50 km/h all of a sudden. As well, the AI always does the same thing; for example, if the car in front of you starts the race by veering off the track once, it'll do the exact same thing every time. That makes it very easy to anticipate when the AI will slow down, thus warning you not to follow them at that area the next race.
Handling - Almost a port of the famed Gran Turismo handling style.
I must admit, after playing GT for the past 8 years, switching over to Test Drive Unlimited was like playing GT5 (an imaginary game). For those who haven't touched Gran Turismo, the handling style is very very drifty, the opposite of arcade style racing like Need for Speed games. There are frequent spinouts, acceleration is more realistic, and crash detection is more realistic. Basically, the physics behind TDU is more realistic than NFS, but less realistic than GT4. Where NFS allowed you to take turns at over 150 km/h, TDU forces you to take them at a more realistic 80 km/h, but still faster than GT4 that makes you turn at about 60 km/h. As realism goes, the more realistic, the more difficult, so TDU isn't going to be a breeze, especially for new racers.
Exploration - First racing game that allows exploration of an area that is in proportion to real-life.
Again, to compare with NFS, Test Drive's mileage system is far more realistic. Travelling 20 km's across the island actually takes a good 10 minutes, making Test Drive the most realistic racer in respect to mileage to date. Another huge aspect of TDU's exploration is the realism in the island's layout. For those who've been to Hawaii, you'll have to attest for the accuracy of the cities, beaches, and districts, but for me, who's never set foot there, the locations are all very convincing. The cities are spread out mainly along the coast, and harbours can be found in bays, and airports are found in only the non-mountainous areas. The innovative GPS also comes into play: you could fast-skip to roads that you've previously travelled through, so that eliminates alot of the unnecessary annoyance for travelling to a far-off point.
Value: 10/10
Although I claimed the races were repetitive and AI uninspiring, the exploration of the island more than makes up for that. Exploring through the island in Test Drive isn't simply running through endless miles of monotonous road. The scenery is exceptionally varied, the driver view actually makes you feel like you're driving your dream car listening to the radio, and the traffic will keep you on your toes as cars WILL actually stop at a red light and stop sign. In other words, exploring Hawaii in Test Drive is most likely the closest you can get to actually driving a Lamborghini in Hawaii without shelling out $2000 for the hotel and plane ticket and $150,000 for the Lamborghini itself.
There's much more that can be said about Test Drive Unlimited, but the highlights are here. The rest will be left for you to discover yourself.
Pros: Detailed graphics, Realistic gameplay, Attention to details (radio, lighting, windows, police).
Cons: Hardware requirements, Repetitive races, Stupid AI, some inaccessible areas that should be accessible (some beaches, some blocked off grassy plains, etc.).