Keeping up the Pokémon greatness
The games in the 3rd generation of Pokémon had a couple of new things compared to it's predecessor. But most of it, it was still a traditional Pokémon trainer journey.
You choose to play as either a boy or a girl, name your character, and then set out on a lengthy adventure as you attempt to become the greatest Pokémon trainer in the world. Along the way, you'll visit a number of different towns, compete against their top Pokémon trainers, talk to a bunch of different people (many of whom give you stuff), fight wild Pokémon on land, on the sea, and underground, race around on a bicycle, surf on a Pokémon's back, and more.
Though the majority of Pokémon battles are one-on-one affairs, there's the occasional opportunity to engage in a new tag-team bouts, with four different Pokémon (2v2) duking it out simultaneously. These are quite fun and allow for some interesting strategies, and unfortunately they aren't nearly common enough. If you want to take a break from all the Pokémon thrashing, you can now put your prized critters through a series of best-in-show events, where they'll appeal to the crowd using their various moves. This is a pretty good new feature, and while there isn't much point to it, since it isn't part of the story and it doesn't yield much of a reward, it's still something to pass the time.