(Yes, one of the mini-games in Bomberman Land is to roll toilet paper.)
There are a number of modes to play through, but the game's focus is its titular Bomberman Land mode. In this story-based journey, Bomberman is sent on a quest to save Bomberman Land by collecting various land pieces, 150 in total. By collecting the right land pieces, Bomberman will be able to unlock more parts of this inexplicably sunken world. To make matters worse, the denizens of this land have seemingly undergone collective amnesia, and will only bestow the "Piece King" (that's you, by the way) a piece when he completes one of the game's 50 mini-games.