This one's stuck in neutral.
Cars 2 on Nintendo DS is the official game of the movie and follows the plot pretty much scene for scene. While it has a decent of amount of content and the presentation is of a high caliber, the single-player campaign does have its issues.
The premise of the single-player mode is sound: follow the story of the movie by switching back and forth between races with Lightning McQueen, and stealth missions with Mater, the rusty old pickup truck mistaken for an American spy. Unfortunately both are tedious and repeat the same content again and again, which quickly sucks out any initial fun.
The racing part loops between the following scenarios: racing against a cultural stereotype car of the current country you're in, knock-out races with three nameless cars, rival races with Francesco, then a World Grand Prix race to finish it off. Each race is done on the same course with marginal differences in the route each time. The easy AI and forgiving hit detection make most of these races incredibly easy to win. It's basically a case of hitting the A button and scraping along the walls to victory. Even half-asleep, it's possible to finish in first place.
The spy missions are no better. One good example would be where you first find and disable "bad" cameras and then place and activate "good" cameras in exactly the same places. After that, there might be a comedy mission where Mater has to collect soda cans and ice cream to cool himself down, but it all boils down to racing around the same open plan level yet again collecting ultimately useless things, placed in almost exactly the same positions every time.
Almost all of these Metal Gear Solid-style sneaking missions were frustrating rather than fun. You could drive right in front of an enemy car and not be seen, yet if your wheels went inside a spotlight you failed your mission. The collision detection was also a bit dodgy, with your car bumping into a wall when it looks as though you're going to clear it, something which could have been avoided if the levels weren't small compared to the relatively large (albeit nice looking) car models.
Being passed back and forth between these two mind-numbingly repetitive styles of mission does not make a fun single-player game.
You could avoid that mode altogether and play standard Grand Prix races, but only a handful are available from the start, so you will have to wade through the monotony to unlock more. Some of the races are quite interesting, such as racing only against the evil Lemon characters or the Sightseeing Cup which changes countries with each race. You can also replay all the missions you've completed in single player, if you really want to.
The racing itself here is quite fun. The handling is generally good and the car models have some degree of weight and shift when driving and sliding around the tracks. The Mario Kart-style powerslide is a nice touch, as are the car-specific abilities such as Lightning's jump and Finn McMissile's invisibility. The cars and tracks are quite detailed and everything moves smoothly without any frame-rate drops, however nothing goes beyond what was achieved in Mario Kart DS back in 2005.
The production values are also noticeable in the voice acting. Preceding and following every campaign mission, there is always a conversation between two of the characters from the movie. Michael Caine's voice is easily spotted as the British spy, for example. The music choices, however, are a little strange, as they are specific to the type of mission or race as opposed to the country or area you are racing in. That means it doesn't matter if you are on a stealth mission in Japan or Germany - you're hearing the same track again and again.
As you'd expect from a Disney production, it's a technically sound game with a decent amount of content, but the tedious nature of most of the levels make this hard to recommend to anyone, other than to Cars 2 fans who only own a DS and are desperate to play as their favorite characters.