Ok, let me get this out of the way first: the demo reminded me of when I started playing the original Deus Ex. With that game I thought, 'yeah, ok, but it's a bit dull'. Well Deus Ex (not the sequel) blew my mind once I got into it and the full version of Forza 2 does much the same (and it doesn't take long to get into either).
It is a sparkling tour-de-force, a marvel of content over style (for once). One of the reviews I read said the graphics aren't all that great and I have to agree. I was a little disappointed at first, and having seen Dirt's graphics, I started to think that maybe I had bought the wrong game, but the feeling didn't last.
Once you start driving you realise what this game is all about. Let me put this in context: I was driving an older American muscle car round Laguna Secca and getting pretty peeved as I kept overshooting and hitting the barrier. But (and this is crucial) I wasn't getting peeved with the game, I was annoyed with the car. Driving a different car round the same track is a completely different experience. In fact, every car drives differently. Even if you change the tyre pressures they drive differently. You actually feel the subtleties in the handling. And that's with the joypad (some achievement). I'm told that with the MS steering wheel it gets even better.
But there is something else. This game is hardcore. It's designed for petrol heads. Well, I'm no petrol head, but I'm still enjoying it. I'm not saying everyone will, but I think that if you like Gotham, you will probably like this.
Faults: as stated, the graphics could be better. They're not bad, just not cutting edge. Apart from that, all I can find wrong with it is that sometimes the menu system could be a little friendlier, but I'm reaching here.
In short, this is the new best driving game on the 360, and possibly on any platform. I would give it five stars, but I'm mean and I don't want the developers to get complacent.