General comments: 
Project Gotham Racing 4 or better known as PGR4 is one of the most intense racing simulations out to date. It is also one of the very few racing games to mix fun with simulation and actually make the concoction work! Project Gotham Racing has come a long way over the past with Bizarre Creations tweaking every aspect of the game to make it perfect. I think they might of just hit the nail right on the head in PGR4 as the new array of cars spanning from "Class G" classics to "Class A" supercars makes the game more diverse than ever. The famous McLaren F1 LM is still in like many of the other high performance supercars, but you haven't seen anything yet as the rarely seen Apollo is up to be thrown around the tracks of PGR, the Apollo like many other rarely seen cars. And as if that isn't enough... Bizarre Creations took those vehicles, threw them to the side and brought in some of the most luxory motorbikes such as Ducati, Kawasaki and many more! Just be cautious though.. These bikes aren't for the feint hearted.
As said before PGR is a racing simulation crossed with fun, this means it has thee cars, thee tracks and now.. Thee bikes. Not only that it has physics better than the last 3 put together and even more. This game truly does stand out amongst the four and if you believe the third was bad, don't be quick to judge the fourth as you can look forward to the following:
Improved physics/graphics
Improved A.I
Improved, inovative Career Mode (Online/Offline)
Improved Multiplayer (Including "TrueSkill" Xbox Live)(Standard 2 player split-screen)
Basic character/car customization (Appearance)
A vast selection of cars/bikes
If you are a PGR fan then this is a must buy, for those who doubt it.. Rent it out and see what you think yourself. I simply wouldn't recommend this game to those who enjoy full simulation racing games or to those who dislike STOCK car racing. All cars in this game are stock and can't be modified apart from in appearance. For everyone else.. ENJOY!
The game is getting on a little in it's age but this review isn't, so it's safe to say that for £15 or $20.. It's a good buy
Graphics: 9 / 10The game gives off a nice slick feel as you see the beam of lights through the night reflect from your car and as you use that dynamic camera to take a glimpse of the audience to the side of you, it flashes past and hell you notice it. Before you know it you will see your opponents rear lights brighten as they slide through the following hair pin, throwing the smoke from the tires around the corner with them. You will follow watching the apex blaze by. I speak like this to say exactly how it would be in slow motion but I tell you what, you won't get chance to see this as you will be having too much fun tailgating the opponent ahead..
Sound: 7/ 10The sound of this game is nothing to rave on about as it's really the usual stuff, you can tell it's more ambient and hell.. There is nothing better than boosting the volume to hear revs of your Ferrari FXX now is there? Then you wonder why it got a "7". Simple, PGR is renown for having a decent playlist and PGR4 is no exception, you will probably boost the sound simply for the music.. Who knows?
Controls: 10 / 10A ten year old could get the hang of these controls and probably play this game with ease, the controls.. Are brilliant.
Gameplay: 9 / 10
Single-player - Single player is great first time around through the Career Mode, from then on you play this game online. There are no buts really unless you are playing side-by-side with a friend. I would not buy this game if you lack the ability to play online, you will lose interest quickly.
Multi-player - Possibly the main part of PGR4 - It allows you to do everything you can in one player along with other players. Your skill in-game is measured using a new tool called "TrueSkill" and this will match you with players in your skill range. You will also find that you can play the usual fun Street Race, Cat & Mouse, Eliminator gametypes along with a couple more you might be surprised about.
Replay value, longevity: 7 / 10
Single-player - The replay value of the single player is minimum. You play this game once and it will be a rarity you pick up your controller to play with the A.I.
Multi-player - You play this game to play online, simple as that from my view. The replay value of this game online is so much more as it allows for much more. And it's always much more fun playing with others online, especially when you can go through the career mode battling against them. Have Fun!
Overall rating: 9 / 10