NFS: Heat is quite good as a racing game - as someone who's come from only playing older entries in the series, the customisation and sense of ownership over your vehicles is certainly a welcome feature.
The driving mechanics are generally pretty solid, as is the world map and the design of the terrain. There's a lot of replayability here because of how much work you can put into any one car in the game - whether you're tweaking the performance, or aesthetic customisation side of things.
Unfortunately, this game is also plagued with certain issues. The largest of these, and probably the one that fans have been most vocal about, is the police (see below).
For those who haven't yet played this game, there are effectively two modes - day, and night. Each has its own set of events with no overlap between the two. During the day, you don't gain any 'heat' (police attention), and completing races and activities earns you money to spend on upgrades. At night, however, you have a heat level, which continually increases from 0 to 5 as you gain more and more 'rep' from completing night events - rep being used to increase your level, and unlock more cars to buy, and higher tiers of performance parts. If you're unfortunate enough to get into a police chase in the early game (which can happen at any time, as the AI director seems to be a big fan of spawning patrolling cops only a few hundred metres ahead of you), it's likely that you'll end up being destroyed, arrested, and lose a significant portion of any money you had when you started the night.
Not only is the police AI incredibly effective at 'rubber-banding' to magically catch up with your car, they also do barely realistic damage to you with even slight nudges at speed. The game also does not tell you this (from memory), but the most effective way (and only way, until you're at a point in the game where you're driving a supercar) to escape a police chase is to jump from any of the ramps scattered around the map (which are frankly far too scarce for this to be an effective solution in many areas), and let the cops crash themselves as they try to follow.

All things said, the game is still pretty fun as a whole. I wouldn't have put so much time into it if everything was frustrating.
7/10

NFS: Heat is quite good as a racing game - as someone who's come from only playing older entries in the series, the customisation and sense of ownership over your vehicles is certainly a welcome feature. The driving mechanics are generally pretty solid, as is the world map and the design of the terrain. There's a lot of replayability here because of how much work you can put into any one car in the game - whether you're tweaking the performance, or aesthetic customisation side of things. Unfortunately, this game is also plagued with certain issues. The largest of these, and probably the one that fans have been most vocal about, is the police (see below). For those who haven't yet played this game, there are effectively two modes - day, and night. Each has its own set of events with no overlap between the two. During the day, you don't gain any 'heat' (police attention), and completing races and activities earns you money to spend on upgrades. At night, however, you have a heat level, which continually increases from 0 to 5 as you gain more and more 'rep' from completing night events - rep being used to increase your level, and unlock more cars to buy, and higher tiers of performance parts. If you're unfortunate enough to get into a police chase in the early game (which can happen at any time, as the AI director seems to be a big fan of spawning patrolling cops only a few hundred metres ahead of you), it's likely that you'll end up being destroyed, arrested, and lose a significant portion of any money you had when you started the night. Not only is the police AI incredibly effective at 'rubber-banding' to magically catch up with your car, they also do barely realistic damage to you with even slight nudges at speed. The game also does not tell you this (from memory), but the most effective way (and only way, until you're at a point in the game where you're driving a supercar) to escape a police chase is to jump from any of the ramps scattered around the map (which are frankly far too scarce for this to be an effective solution in many areas), and let the cops crash themselves as they try to follow. All things said, the game is still pretty fun as a whole. I wouldn't have put so much time into it if everything was frustrating. 7/10