The DS version of Mario Kart is a step forwards from the rest of the series, with new innovations, but keeps the fun.
There are over 30 tracks to choose from, and half are available to you in each area of the game when you start. The first menu contains the options of Single Player, Mulitplayer, Nintendo WFC (Wifi Connection), Records, and Options. Single Player mode holds the Grand Prix, where you race in a racing "cup" over the course of the 4 tracks of that cup. Time Trials allow you to race against your own ghost, or if you become good enough, an unlocked staff member ghost,to compete for the best time. VS allows you to compete on tracks of your choosing against 7 AI players to win a Vs round, you also chose how many tracks you race on to determine the winner. In Battle Mode, you choose to either compete in a Balloon Battle, where you use items to pop your opponent's balloons, or Shine Runners, where you compete for shine stars, a throwback to Super Mario Sunshine. Finally, you can do Mission mode and complete selected missions, like collecting coins or driving backwards.
New tracks can be unlocked in Vs, Time Trials, and Grand Prix, and there are 3 difficulty levels for all of them. The tracks are separated into fours, each group of four makes a "cup", and 4 cups make a prix. There are two prixes, the retro prix (tracks from past Mario Karts) and the nitro grand prix, which are new and original to this game. My favorite track has been Sky Garden since I played it on the GBA version, and I was delighted to find it in here, revamped beautifully. If you beat all 4 cups on one difficulty level in 1 prix, in the Grand Prix, you can unlock new characters, and on the 150cc Prixes, you can unlock the 150cc Mirror class, which is a mirror course of all of the courses. You can also unlock new karts for each character, there are a total of 7 for each character. To unlock these however, you must practice your skills, and you HAVE to know how to turbo boost, or you will never become a great player. Lastly, items are the difference between 1st and 4th many times, so learn to use them effectively!
If you're like many people though, you bought this game for the Wifi. Nintendo's wifi connection was easy for me to set up. I already have a router, a linksys, and in seconds I was connected and playing against people all over the world. A downside to this game is that some tracks are unavailable in the WiFi version. It would have been nice to have all tracks available, but there was some issue with how the tracks would work when streamed over the wifi.
Graphics: Amazing. Absolutely beautiful for the DS. This is some of the best use of the DS's graphical capabilities that i've ever seen. I've never had shoddy graphic moments, and the colors stay crisp and don't blend.
Gameplay: Easy to learn the basics, but you need to practice to get good. Sometimes it feels like your pad is reacting too much when you try to turbo boost, which screws me up while taking close corners. Other than that, it's executed wonderfully. I personally love all of the items, though the blue shell seems to appear way too often. The computer is at too much of an advantage when you've been kicking butt in 150cc mode, and at the last second somebody half a track away blue shells you and beats you to the finish. It makes it more nervewracking, but it's just a tad too annoying sometimes.
Sound: Nothing to complain about much, except sometimes there's just a tad too much of sound going on.
Overall: This game is definitely worth picking up. even if you have no access to wifi or friends to play with, it's still worth it's weight in gold. This is the best Kart I've played, though I've only played 2, so I don't have much to compare to, but still, get the game, you won't regret it.