..I personally love it.
I'd recommend buying cars before you buy many performance upgrades.
Unlike the console versions, there is no free-roaming mode. You simply go through the Underground menu and pick a level you have unlocked, or you let the DS throw you a random challenge. You can whizz through a decent chunk of the Drag Races quickly before you hit the difficulty threshold that will require you buy better cars, but Own-The-Zone and Circuit Racing find you hitting that point much sooner.
CONTENT
Once you start getting different cars and engaging in different modes, there is A LOT to do. They re-use various tracks, going in reverse, with or without traffic, and traffic also comes in different weights. There are all sorts of rule variations too. In Own the Zone you're competing to perform the best in 4 different areas of the race map. The one with the most zones wins - if it's a draw, whoever crosses the finish line first wins. As a subset of the Circuit Racing mode - there's time trial races, and normal racing... there's Lap Knock Out and stuff too... On each lap completion, the car in last position pulls up from the race. Last car racing wins. The various modes are selectable from the main menu as "Go Underground" or something to that effect. Each mode has a sub menu of levels. For example Circuit Racing has a sub menu of Level 1, Level 2 and Level 3. Each of these has a whole bunch of challenges inside to conquer. Same thing for own the Zone. Drag Racing was initially my favourite part of the game. Then you've got the minigames and the Garage.
The minigames are ultra simplistic. It's laughable that they are presented under the guise of "engine tuning", "nitro tuning" etc. because for the most part it's holding a lever with the stylus to keep a wavering ball within a given path, or using precise timing to tap one of six buttons on the touch screen as an appropriately coloured blob races towards a line (a bit like Donkey Konga, but without music and harder). They're not the main draw of the game obviously, and they're not particularly good, but their inclusion isn't obnoxious or obtrusive... it's better that they're there than not.
CUSTOMISATION
Visual and performance upgrades for your cars have to be unlocked as you progress through the Underground mode. So early on, you'll only be able to use certain rims, certain body work jobs, certain hood bevels, certain paints, neons, certain decals, certain custom decals etc. Once you've bought an upgrade you can use it on all of your cars. You start with what look like pretty lame cars. But with a bit of work they end up looking great! It's satisfying. You do the same for performance... adding better suspension, turbo, drivetrain etc. When you add things like Nitros, it actually alters the function of the touch screen when you're in a race...
GAMEPLAY: AI AND INTERFACE
General control is sensitive but good. You only need to tap the D-pad directions slightly in order to change your course. Holding left or right for any greater amount of time will have you skidding about, and probably stopped up against a wall or a truck. Taking corners is often done easier by releasing the grip on the acceleration as you approach and then taking the bend before applying speed again. The breaks can also do a good job... "R" being good for a sharp handbrake turn.
When you add things like Nitro canisters, you can tap the touch screen when in mid-race, and four Nitro canisters will appear on it. You can then choose which one you wanna burn off for a boost. This is a little fiddly (sometimes it's better to just press L or Y in a frantic race) but its cool none the less.
Racing with the first four cars is immensely frustrating. The handling is worse than it is on later cars, the speed is often nearly-enough but not quite enough. Sometimes if your car isn't as fast as the cars coming up behind you, they can hit you from behind or slightly from the side -- and rather than just shunting you as it would in other games, it sends your car spinning and flipping out of control! Games don't typically get me angry these days, but I was sitting in my room the other day - leading a race for two laps, when suddenly I ran into an oncoming truck. The three other racers whizzed past me and crossed the finishing line. I had not been breathing for the last ten seconds, so I took a good deep breath and tried to restrain myself... "FFFFFFFF..."
I couldn't restrain it. "****ING ****** ****!"
Expletives poured out from my mouth for a good 2 minutes and the urge to snap the DS was very high indeed. I happen to think it's good though. This is challenge. If I don't want it to happen? I've simply gotta be good enough to not hit cars head on!
Now as I've gotten further in the game, I'm starting to like the cars. The handling is better, the speed is great... those videos on IGN? They don't do justice to how quick this game can get. It's probably one of the most graphically impressive games on DS too, even if there is quite bad pop up sometimes. It has nice lighting in particular. Comparisons to PSP games will yield no constructive comment on the quality of this game. As for the AI? Well I have my suspicions as to why people don't like it. I believe that on most levels the game plays "catch up". When you do a custom race this is an option you can turn on or off. This isn't an option in the main single player game. It IS annoying when you've worked hard to get where you are, you make one mistake and then everybody passes you... but having said that, if the option to turn it off had of been there, I probably would have whizzed through this game and put it to rest in a cupboard already.
What I want in the sequel:
Single card multiplayer mode if possible. If it means less tracks or cars in that mode, that's fine.
Online play.
A chat mode incorporated into that online functionality.
More than two camera angles.
Bigger custom-decals or more data banks for them.
An even better interface for drawing them. A Zoom function perhaps?
An option to turn rubber band AI off in the main game.
Other than this? More of the same!
