Update: I was unfortunately not aware of Shamus Young's severe criticism of Fallout 3 available here to link in the original piece and I regret that. It dovetails rather nicely with what I've written and it's much better executed than my piece. I strongly recommend anyone...
Gran Turismo 3 wasn't really a game. Oh sure, it looked very much like a game. In fact, it looked very much like a good game. Not to mention that it simply looked good. But with the powers of hindsight, we now all know its purpouse was not to give us a full gaming experience.
Its purpouse was "merely" to set a Standard until Polyphony digital could release the actual racing game once they really got to terms with the PS2 technology. It was telling the other car game developers (especially those that went for realistic track racing) that "this is but a taste of what you're going to have to beat.". That explains how there were less cars than in the original Gran Turismo for PS1, and only two more tracks than in GT2.
And then, after doing some more test runs, we've got Gran Turismo 4. And from the moment the intro starts, playing "Moon over the Castle", you realise it. This is what we were really waiting for, what GT3 was only giving us a glimmer of. Just about everything is crisper, cleaner, better, and the game is simply bigger in almost all aspects. If there is a fault in here, it's that there isn't that much change to the actual gameplay, and that some menus get more confusing to navigate.
700 cars, including the very first manufactured car delivered by what is today Daim-Mercedes, back from the 19th century. And some fantasy cars specifically designed for the game. If that doesn't satisfy your need for cars, it's because you were specifically looking for a Ferrarri, which is just about the only attractive car brand the game developers couldn't make a deal with. And me, I prefer the Jaguar Xj220 Road Car in Mistral Metallic for a real sports car that also shows elegance. Ferrarri's looks are too.. brawling, too noisy, too edgy. Anyway, point is, there should be more than enough cars here for everyone. And then some.
Then there are the tracks, which pretty much illustrate the changes from GT3. Several of them are in fact minor variations (such as there being a 80s version and a 90s version of the famous Fuji track in Japan). The differences may seem small, but they will in fact often make a real difference in how you learn the track. But not always, though, meaning that you have to take the "50 tracks" claim with a grain of salt.
The controls are pretty much the same, except tightened up a bit to make the most out of the crude things that pass for analog sticks on the PS2 controller. One difference is that the right analog stick is automatically always used for stepping on the gas and breaking, which is the best way to play this game if you can't get a steering wheel controller. Just saying this if you're looking for the option to put this on but can't find it. Also, if you pause the game and then unpause it, the game waits a bit longer than in GT3 before the driving starts up again, to allow you to get your thumb back on said right stick. That's definitely a small detail that makes a big difference.
The main menu in Gran Turismo mode has gotten a major overhaul. It can be overwhelming at first, but you'll eventually learn how to deal with it. And when you do, it mostly feels better. A good thing is that those car races designed for specific car models have been moved to be placed as a submenu for that very manufacturer, meaning you don't have to switch between car manufacturer and main racing menu endlessly. And when you win a car, you can also see from the main menu whether it's eligible for one of these races. On the flip side, the tuning parts shop is also moved as a submenu for each manufacturer, instead of having it in one place like it used to. But at least you'll always be pointed in the right direction if you're unsure where exactly you're going to buy parts for some model you've never heard of before.
The garage menu has also underwent some changes, but while the design is more pleasing on the eye, it annoys me to hell that the game won't remember what particular setting I've put in, but have to redo it all over again. Sloppy, sloppy! Another thing is that oil changing and car washing's having added some extra animations that are completely worthless, and only adds time wasted doing nothing.
But, so far I've mostly only talked about changes to an existing formula. But what is actually new? Well, I must admit I have only played Gran Turismo 3, not the Tokyo thing nor that proto-version of GT4, so I'm not totally sure if there's anything -really- new. Anyway, what was not there at all in Gran Turismo 3 was the "mission races", which are small races with pre-chosen cars. Basically, you always start on last place, and then you're supposed to overtake the car or cars in front of you. You have either a small stretch of a lap, one lap, or three entire laps to do this in. The main thing here is a) to drive almost perfectly and b) to use the drafting technique (driving closely behind another car to decrease air resistance) to gain that extra speed you need. And you'll always win with but a small margin. A tip here is to do the four draft races taking place on the Test Course as soon as possible. The prize car is just what you need to get done with many of the early races as quickly as possible, and then you can sell it for a buttload of cash. After all, if you've played any of the previous games, you do want to get to the hard stuff as soon as possible, right?
Another new thing (from GT3) is the B-Spec mode (available in all normal races), in which you act like a team leader giving orders to the driver instead of driving the car yourself. I'm sure it's supposed to be interesting in that you can feel like a boss telling the man what to do... But I always ended up just using it so that I could read a book while the boring races against slow cars went on. I'm pretty sure that's not what it's meant for, but it's just not much fun in itself.
The rally racing has been given a revamp, with new snow tracks, and city tracks so tight and narrow that it makes Cote d'âzur look like the Fuji Speedway. They also carry a new penalty, in that if you smash your front too hard into something, you'll get a 5-second period where you can only drive in 50kph. Which means you can't just freely use the walls and fences to break your speed like you could in the city racing tracks of GT3. The problem is that the game doesn't differentiate between when you're trying to cheat, and when the opponent is making you smash into the wall. Oh well, at least it's not there in the ordinary track racing mode.
Graphically, it's pretty much everything you expect. And you were expecting a great deal after GT3, right? The cars look marginally better (but the were already looking so good, one could hardly improve much there as long as we're on a PS2), while the tracks are improved a bit more than that. The audience look better as well... at least as long as you ensure to drive past in high speed. The music is pretty much also as expected, and naturally, you can always choose which soundtracks are accompagnying the always stunning replays. New is that now you can also play them in their entirety in the music menu, not just hearing a small taste. Again, small but important improvement.
Even if the AI isn't really changed at all, this is The Track Racing Car Game. It's going to last longer than most of you players will. There is only one thing, though: If you have already played all the previous GT games to death and are starting to get bored with an incredibly well executed car game that is nevertheless feeling a bit sterile, then you might want to think twice. There is a lot more stuff here, but the core of the game is still essentially the same, just so you're aware of this.
But if you just can't get enough of this kind of racing, and your obsessive-compulsive brain is itching with getting all those new cars in your garage, then go for it. And if you have so far managed to miss the series in its entirety, then also go for it. And get yourself that Jaguar XJ220 Road Car in your garage as soon as possible, preferrably in Mistral Metallic. It's still a beauty.