You make the Pokémon dash by sliding the stylus along the touch screen. The quicker you do it the quicker Pikachu moves. However running is not the only option...you have Balloon Races, Falling and much more. But you cannot just go taking shortcuts, you have to pass through Checkpoints that are shaped like Pokéballs and other items, some even give you boosts when you go over.
However, it is capable of linking with Pokémon Emerald...if you put an Emerald Cartridge into the Nintendo DS and play this game, it will unlock some more tracks for you
It's even Multiplayer allowing up to 6 People to play at once!
I have to say, it's similar to all Animé based racing games, such as Mario Kart. Mind you, they are all special in their own way. I believe that this game is probably more a collectors item, as it is very easy to finish within a short amount of time.
Despite all this, it's a very fun game, and I reccomend you get out there, Buy a Nintendo DS, and grab a copy of Pokémon Dash!