I thought it was Gran Turismo 4 in High Def?
That's what people say to describe it easier. It was a slight improved GT4 physics engine running on a PS3. But in fact, GT HD was meant to be a full game with many plans ahead.
However, that plan was not going to work.
As said before, GT HD was available in the store of the 3 main regions for a limited time, and in Japan they got a disc version. But I can not stress this enough, it is very, VERY, rare. With this I don't mean you won't find one, it's just that when you do, it will cost nearly half as much as your house (obviously not, but you get the point).
Not to mention that the game might be in Japanese...
Isn't that stuff he did "hacking" in a sense? Just curious.
If you want to lable it that way, go ahead. But it's a lot more complicated than that
Every single game that you've play in your life responds to a series of codes, those codes are a line of several numbers. While the game running, it will use thoes codes to present to you several elements while you play. Some times, you may look at a tree on level 3, and find it again on level 50, but it's the exact same tree, same code, same textures.
You may even find a tree inside these codes that was never used in the game, however, it's form, texture, color, or anything else might.
That's where all these hidden tracks come from. They were made to test the car physics, and how the game could handle it. That's why you never find them polished up, and have a lot of bugs and missing backgrounds
As I said before, all this is a series of number, and if you were the one responsible of testing all this, would you really want to waste your time looking trough a endless series of numbers just to remove a single element from the game? Of course not, that would take forever, not to mention you'd be wasting precious time of the develop of the game.
So instead, they program the game to skip these codes, so that no one can see them. It's not like they are hiding a secret from you, just think of it as "deleted scenes" that you find on the extras of a DVD movie.
GT5's Missing Cars? The cars not in GT5 from previous games? (e.g. DB7 Volante from gt1, fpvs and auto union streamline) Is there already one of these? If not I'll create one! I only have GT, GT3, GT4 and GT5 though, so I'll need a couple of people to help.
edit:
this doesn't have the old cars but this is what i'll do.
It would be pointless creating yet another thread about the exact same subject. What you could do is continuing posting on that same thread, regardless if the OP doesn't update it any more.
I'm planing to do a similar thread like this one but about locations. However, reason I won't it's because I'm waiting and see if our friend Van does on this thread instead.