Those of you who liked NFS:Most Wanted will enjoy NFS:Carbon as well. I've been playing it for about a week now (six hours into it I'm 50% done).
Carbon takes the NFS series out of the rural woods (like Most Wanted) and back into neon-lit cityscapes.
Think of NFS:Carbon as the racing version of Risk. After choosing a car from one of three categories (tuner, muscle, or exotic), you'll begin racing. The city map is divided up into four major regions, with each region sub-divided into smaller counties. Each county contains multiple races; win the races to take possession of a county, win over the counties to eventually take over a region. Winning a race also unlocks car upgrades that can then be purchased.
Most of the races are the same as before; there are circuit races, sprints, speed traps and timed races. NFS dropped the "drag racing" game from MW (a really annoying race which forced gamers to steer with the left analog stick while shifting with the right) and replaced it with "drifting" races. Drifts are a completely different engine altogether. They're frustrating at first to learn but kind of fun after a while. Basically, drivers must drift their cars around a track. Points are awarded for the length and duration of a drift; multipliers are added for linking drifts together (you'll need to do that to score enough to win) and drifts end when you spin out or hit a wall.
After winning over an entire region you'll be challenged by a boss. After beating the boss in a grueling sprint race, you'll have to own them in a canyon race as well. You'll have to race through the canyon twice, back to back. The first time, you'll be chasing the boss, and be awarded points for how close you trail them. The second lap through you'll be in the lead with him chasing you. Like most previous NFS games, you'll need to continually upgrade your car with better parts to beat the bosses' superfast rides.
The other new addition to NFS:Carbon is the addition of wingmen. You can now acquire racing partners who will join you in races and offer you bonuses on and off the track. Different wingmen unlock different car modifications, parts, discounts, or heat levels. There are three flavors of wingmen: drafters (who will slingshot you ahead in a race), scouts (who zoom ahead and find all the track's shortcuts for you) and blockers (who will bash into opponents cars for you, slowing them down). The wingmen are a mixed bag of success. More often than not they just got in my way. Blockers, if in front of you when activated, will slam on their brakes, smashing into you and allowing the competition to zoom past! The drafters usually slingshotted me into an awaiting wall. The scouts are a little too handy -- after pointing out all the tracks' shortcuts, I began winning races by 30+ seconds.
The car modification system is back and offers more features than ever. After purchasing a car you can add one of a million body kits, wheel styles, spoilers, etc. Don't forget paint colors, graphics, flames, symbols, etc. Each of these applied items can now be repositioned, flipped, rotated, or skewed. A new "autosculpting" feature allows you to mix and match parts of body kits or even create new parts. Personally I just paint all my cars black and stick flames on them, but the game allows you to customize your cars to your heart's content.
The cars in the game all drive differently (especially the different classes of car). It was kind of frustrating to find that the RX-7 (a tier 2 car) handles much worse than the RX-8 (a tier one car) after spending all my money on it. Like real life, the tuner cars are the cheapest, handle sharp but need upgrades for real speed. The muscle cars (your first option is a first series SS Camaro), like real life, go fast in straight away and steer like ass. The exotics are expensive but fast. There are 40+ cars that can eventually be unlocked. Like previous versions of the game, cars can be bought or sold (to recoup money).
My only complaint about the game so far is that the races are pretty easy. Only a lack of time (and not skill) has kept me from tearing through the entire game. The canyon races are difficult; the second one took me over an hour to finally beat (I finally quit, upgraded my car, and returned to kick ass), but most other races in the game are easy to beat on the first attempt (especially when using a scout or a blocker).
Like NFS:MW, Carbon has a "mysterious" back story that unfolds through FMV cut scenes as you win races, but the thin non-original plot (ooh, someone exchanged one red bag full of money with another one!) seems secondary to the racing.
If you like NFS racing games, Carbon is worth picking up. The audio and visuals will show off your system. Next-gen version of the game (360/PS3) also support online play. The Xbox/PS2 versions do not.