It's kind of basic in terms of features, but the racing is fantastic.
The game is not very feature rich, quite the opposite really. You've got a career mode, a quick race mode, and basic online functionality. The game didn't even ship with a LAN mode, they added that with the last patch. It doesn't have that many cars, and most are the type of cars you see quite often on the roads (VW Golf, Ford Focus, Honda Civic etc.). It has a limited selection of tracks, with no weather effects or day/night cycle, or cop pursuits. Even the scenery is limited to the districts of a rather common looking city, with a generic downtown area, a generic residential district, a typical looking chinatown, and your average industrial area. All that said, why is this game worth playing? Well, the concessions made in all those areas pay off when it comes to racing.
Truly, NFS:U delivers one of the best arcade racing experiences around. Cars can be a little loose (turn off traction control and you'll be drifting all the way), but this just adds to the excitement. You'll see what I mean when you get to drive through a three meter wide alley filled with bumps and obstacles at 200+ km/h. It's pulse-raising. Also, the physics for high-speed collisions are a bit mental. Hitting traffic or losing control of the car will mean a lot of time lost (on high difficulty, this usually means you've lost any hope of winning), as it should be. There is one disappointing aspect here however: there is no car damage in this game, not even visual. Disappointing, but it's something you get used to.
The career mode is very straightforward. It's basically made up of 100+ events, tied together by various cutscenes and audio snippets. The story is inconsequential though, what matters is racing through all those events and reaching the top of the charts for the various game modes. And the nice thing about the career mode is the gradual difficulty curve; early races are quite easy, but the game scales in difficulty quite nicely, to the point that you need to be perfection incarnate to win some of the latter events.
However, the game's style can be annoying. It tries to imitate The Fast and The Furious, but all the 'rad' street racer lingo gets old really fast. Then there's the soundtrack, which contains some songs that are just not suitable for a racing game. I imagine they were picked because they were trendy at the time. Thankfully, some of the songs are genuinely good (from the likes of Asian Dub Foundation, BT, and Crystal Method), so it's not all bad.
When it comes to game modes, NFS:U relies on the classic Circuit and Sprint modes for most of the time, and adds Drift and Drag to the line-up for a bit more variety. All modes play really well, with Circuit and Drag being probably the most pulse-raising.
Visually, NFS:U held up well over the years, despite the lack pf weather effects, or a day/night cycle. Racing always takes place during the night, which explains why traffic is so low. And the road looks wet, like after one serious downpour (again, there are no weather effects in the game, this is just the default state of the road) while city lights and banners of all colors abound. And lights have this trippy trail effect, which coupled with the brutal motion blur at high speed, makes you feel like you've been blasted back to the haze of the 60s and 70s.
In closing, if you want a fun arcade racer, this is it. Trust me, you'll forget all about the flaws I've mentioned in this review once you play a few races. Peace!