There are (if unlocked) 8 Grand Prix - worlds available, each consisting of four racetracks. One can choose, each with two different cars and unlock over time more pawns (bone dry, Daisy) between different drivers (Mario, Luigi, Peach, Bowser, Donkey Kong, Wario, Toad, Yoshi).
The race tracks are designed very fun and varied.
Toll I also think that in addition to the Grand Prix and Time Trial also can play racing missions.
Of course a fun time the "adversarial driving" by means of wireless data transmission - even with just one Game Card, but with reduced range.
That the individual vehicles are very different rates, one can see both point of criticism as well as a challenge.
It's really very, very difficult with Daisy's standard vehicle to undercut a Time of Yoshi Eggs mobile ...