Overall Mario Kart:DD is an excellent game. The graphics are great, the sound is fantastic and the gameplay is outstanding. Mario Kart DD offers a few upgrades over Mario Kart 64. The first is the tremendous amount of characters available and use of 2 characters on each cart. They can be paired how ever you like, each combination giving you different rankings in speed, acceleration and weight. The character combination also determines what type of Kart is available to use. The three kart classes are light, medium and heavy are detemined by the characters you choose as well. Echa character also has their own type of special attack. Mario/Luigi has fireballs, Wario/Waluigi has bombs, Peach/Daisy have a Heart Protection and so on. Another nice upside to this game is how everything to so well tied together to the Nintendo & Mario franchise.
The graphics are sharp, colorful and very easy on the eyes. The music & sound is completely superb, especially when used in combination with a surround sound system. Gameplay doesn't get much better than this. On single person mode, you can either choose to play Grand Prix (race for a cup vs computer) or Time Trials. Grand Prix offers 50, 100 and 150cc classes to compete in. From the start of the game you can choose from the Mushroom, Flower or Star Cups with a Special Cup as an unlockable. Each Cup has four different races that you must compete in. For each place you finish, there is a 2 point increment. For 1st-10 points, 2nd-8 Points, etc.. At the end of each race there is also a tally for the racers standings in the cup. Each time you win a gold cup; there is usually a new kart that is unlocked.
There are a few downsides to this game. The first is the lack of customizable controls. Another downside is the lack of number of courses. There could have been at least twice the number for courses included in the game.