Pokemon Pearl is a great game, it has what made the other pokemon games cool and  much more. You definitely spend a whole lot more time on this game then the others, but not in a bad way. As usual there are 3 starters Grass,Fire,Water which later end up being Grass/Ground, Fire/Fighting, and Water/Steel. There are 8 gyms and the Elite 4 all of which you beat by training other pokemon and adding them to your 6 man/pokemon team. After the Elite 4 you can try and see all of the pokemon native to the region and obtain the national pokedex. Now a LOT of things come after this, one that is a very neat thing is the Pal Park which enables you to import pokemon from the GBA versions Ruby, Sapphire, Emerald, FireRed, and Leafgreen to Pearl.

I'll add some more stuff later.