A shorter, streamlined version of Most Wanted
Need for Speed: Carbon continues essentially right where Most Wanted left off, with most of the core mechanics staying pretty much the same. The biggest changes in Carbon aren't so much what it adds, but what it removes. The police chases which have been a large part in Most Wanted and were a required part of the game, are now only a random occurence that can be triggered randomly while racing. There is no longer a need to actively seek out police chases, destroy a given number of police cars, hold a chase for a given number of minutes or destroy property. This in turn makes the police chases feel a little weird, as they are now little more then a random annoyancy and mechanics build around them feel a little superfluously. For example the chases can still escalate with faster and heavier police cars joining the chase, but without a reason to keep the chases going, there is hardly ever enough time for them to actually escalet. The pursuit breaker also don't get as much use as they used to, as it now seems much easier to just race away from the police, instead of trying to destroy police cars with the pursuit breakers.
The drag racing from Most Wanted is gone as well, replaced by two new race types: canyon races and drift races. The Canyon races are one on one chases down a road at night and the drift races require skillfull drifting around corners to collect points.
The rest of the game is much the same as before, you have to complete a number of races to unlock a race against a boss and that in turn will unlock more races that will give you access to another boss. In Carbon there are only five bosses you have to fight, compared to the 15 in Most Wanted and the game is substantially shorter as a result. The game tries to make things more interesting in adding terrain control mechanics, but ultimativly that mechanics is without effect, as having control over a given area doesn't really change anything and wants you gain control you have already finished all the mandatory races in that area anyway. The open world aspects of the game are still present, but just as in Most Wanted, they are rarely used for anything, as you can fast travel to all events. Upgrading your car is available as well and as before, it's kind of useless, as there is no need to customize cars for a specific event or anything like that.
One new aspect of Carbon are the wingmen, those are team members that drive with you and can provide support in the form of blocking opponents, given you a boost by driving in their slipstream or by showing you the secret passages on a race track. The overall impact of the wingmen on the game isn't all that large, but they provide a welcome addition and add a bit more strategy to the races, as you have to time their use to make the most of them. It can also simply be a bit more fun trying to hit the slipstream of a team mate, then just driving alone. The wingmen however feel underused, the police chases look like they would have been the ideal place for the wingman to play a larger role, but they don't, when a police chase starts the wingman simply drives away instead of helping you and with the police changes barely playing a role in the game to begin with, it wouldn't have mattered either way. The open world aspects of the game also feel even more downsized from Most Wanted, as you can now instant-jump to all events and locations, thus with the police chases gone there is basically no reason left to freely drive around the city.
The FMV sequences got a little boost in Carbon, they are now interwoven into the game a little more and you see a new one every hour or two of gameplay, which makes them much more balanced then in Most Wanted, where you only had them at the start of the game and then at the very end, 30 hours later. The story is still rather basic with just a bit of rivalry and betrayal, nothing spectacular, but silly enough to be entertaining. The introduction of 3D character models, which you will see at the race start, feels a bit unnecessary, while they allow some additional dialog, it feels weird switching from FMV sequences over to 3D graphics. What makes the situation worse, is that not all characters are equally split between FMV and 3D, some only exist as 3D characters, some only as FMV and some as both. This makes everything feel a little disjoint.
Overall Need for Speed: Carbon is bit hit and miss. I liked the heavier focus on FMV sequences and the wingmen, but the reduction of the police chases is rather disappointing. The lack of police chases streamlines the game and removes a lot of the frustration that they could cause in Most Wanted, but it also removes one of the most fun parts of Most Wanted and leaves not much reason to drive around in the open city, which in turn means that you never properly learn the terrain. The reduction of game length from 30h to 10h is welcome, as Most Wanted ended up feeling like a lot of cheap grind, which Carbon due to it's shortness never does. As with Most Wanted however it feels like the game was a little rushed and could have used more polish, there are to many mechanics that never have much or any impact on the actual game and a lot of potential for further enhancements that stays unused. Thus Carbon ends up feeling more like a mission disc for Most Wanted then a real sequel.