I first came across this game as a demo in Driv3r. I was bored and figured hey, why not try it.
It only had a single character (Hot Shot) and the first half or so of the first level... but damn if I wasn't hooked almost immediately. The customizable loadouts were great, the graphics (for the PS2) were great, transforming was fun (if not often necessary), the exploration tracking down every mini-con... it definitely made me sit up and try to track down the full game.
And the demo was definitely representative of the full game. I'd still play it today, very happily.
It's a little on the short side, when all's said and done? But far better that, with a game you can replay several times over without getting bored, than a game that overstays its welcome.