Some of the cutest fun you can have, with something for everyone.
Your character is a monkey. He's in a ball. The story line is great for the kiddies, but like the cut-scenes, is kind of weak and unnecessary. So I'm going to get right into the game-play.
Your monkey has to roll across, down, and around various floating, sliding, and turning platforms to get to the goal at the end. The trick to the controls is that you don't actually control the monkey. You control the angle of the platforms. So, to make your ball roll forward, you slant the floor on a downward angle. This adds a unique aspect to the game play. The controls are responsive, and allows for subtle movement. This also makes the controls simple (just the analog stick a-la Katamari), and easy to learn but difficult to master all the nuances.
One stage or world is composed of multiple levels. You have a choice as to which levels you complete to get you to the next world. So you can take all the easy levels to minimize difficulty, complete all the hard levels for some extreme challenge, or complete all the levels available to submit to your Monkey Ball dreams. Although the whole feel of the game seems to be geared to the kids, there is definite challenge and frustration here to be had alongside the fun.
There's also a range of mini, multi-player, and party games available, which makes it not only entertaining for the family, but fun for the family to play together. The extra games range from quick and simple (monkey bowling - aim and fire) to a little more exciting and in-depth (competitive racing and flying monkey glider shooting). The look of the game is very bright and colourful, with child-like characters. The music is fit for the game, and classic Sega.
Definitely fun if you want something to play for: a change of pace, with the family, or with someone who's not usually into gaming.