Possibly the most fun game ever. A throwback to the old Need for Speed: Hot Pursuit days, the latest incarnation combines the adrenaline-filled cop chases with the open, free-roam city of Need for Speed Underground 2.
The cops sound and act incredibly realistic. The first time I played it I was blown away by the way the cops interact with each other and work as a team to take you down. Then I skidded into the golf course and cops started spawning in the greens and it was suddenly a whole lot less realistic.

The challenges in the demo are all quite fun. The roadblock challenge is what sold me though. You have to get enough police attention to make them set up a roadblock. You need to bust through Six (6) roadblocks and then evade the cops. You evade the cops by trying to lose them, the inner-city and campus areas are the best for this. You can also trigger things to break, ie. by driving through the supports on the tyre shop, the giant tyre ontop will break off and fall on any oncoming cops. There are several of these triggers all around the city. Once you have evaded the cops they will canvas the area you were last seen in trying to find you, and if they don't they will expand their area. While they are doing this you have a 'cooldown' meter that slowly ticks down. Once it has filled up you have successfully evaded the cops and you either win or lose depending on how many roadblocks you busted through. If you haven't quite finished the challenge and you evade them, you can backtrack to get the cops attention. There are a few hiding spots around the city aswell, they appear as little blue circles on your radar. While you sit in these areas your cooldown meter goes faster.
The evasion challenge is pretty much the same as above but without the roadblock. I suggest this for noobs, the green hatchback you get is fast and agile and more than able to evade the cops in no time at all.
The final challenge in the demo is the tollbooth challenge, it's pretty much a solo sprint from one tollbooth to another with a twist, there are cops. When a cop sees you in this mode you get this wicked blue and white, prince of persia-ery slow down effect. This effect also occurs whenever you use your 'speed-breaker' which is kind of like bullet time for racers.

Ofcourse the 'quick race' mode is still there for you guys that like that kind of thing. The 'story' mode for this one is called "The Blacklist" and isn't availble for play in the demo, unlike the NFSU2 demo which featured part of the story.

You can grab the demo from the usual places, it hits retail on the 16th/17th.