The object of single player Monkey Ball is to guide your furry friend to the end of the puzzle like platform by controlling  the angle of the platform your Monkey is on, you do this by tilting the ground in different directions, this causes the ball your Monkey is encased in to roll in the desired direction, with speed increasing the more you tip. The aim is to get to the end of the level while collecting bananas and trying to avoid tipping off the edge of the platform, unfortunately your cause is not helped in later levels were the developer has made it as difficult as possible for you by adding all manner of object to get in your way.