Very hard, but great fun.
From a distance, the graphics look great (for a PS game) However when you look closer there are a lot of polygons you can clearly see, and the buildings all look the same in each city, with the exception of Las Vegas. The game also suffers from horrible pop in that is always there, and frame rate issues. Usually, the frame rate is great, but when it slows down, it actually freezes, making you have to reset the console.
Gameplay: 8/10
This game is great fun, but way too hard. You will find yourself doing missions over and over again, either because you lost somebody you were meant to be chasing, or because you got out your car to get a new one, and lost him then. Another problem is that when the police are chasing you, you cannot actually get out of your car and get a new one if yours is highly damaged.
However, running from the cops is great fun, and the game never feels boring, or overly repetitive, thanks to the great story and 4 different cities to explore.
Sound: 10/10
There are no complaints about the sound. Tyre squealing, burnouts, engines, horns, door noises and crashing all use realistic sounding effects. All the car engines sound different and the voice acting is good.
Overall a great fun game, just be prepared for a steep learning curve!!