To put it simply,
Magic Ball 2 is just a fun puzzle game that keeps you coming back and urges you to play just one level more instead of messing with whatever you should really be doing at the moment (like writing reviews for example).
The simple premise that has been used for years means that just about anyone knows the basic rules of the game. Use your paddle (a space ship, in this case) to keep the bouncing ball in the arena, while attempting to destroy all the bricks in the level. But like I said above, Magic Ball 2 isn't any ordinary Breakout game.
Besides the stacking blocks and fun to look at levels, Magic Ball 2 also gives your ship and the ball(s) the ability to use pick-ups. One of these modifiers can increase your ball's size, so it can plow through pretty much any block in its path and not bounce back. Another one makes the ball explosive, so that any block near the one you hit blows up as well. What's best about these power-ups is that they can be combined -- yes that's right, you can end up with a large explosive ball that will rake in the points like nothing else. Combine those power-ups with the one that splits your ball into three and not only will you be destroying pretty much anything on the field, but you will be throwing your ship back and forth across the screen trying to keep them all on the playing area (and just in case you were wondering, yes you can pick up another 3-ball modifier to have 9 large explosive projectiles bouncing all over the screen).
The ball isn't the only thing that can be modified by pick-ups, either. Some of the released modifiers can enhance your ship's paddle. You will be able to increase the paddle's width, make it magnetic (this is really handy when you have a half a dozen balls or so on the field) or even get the balls attached to the paddle with a rubber band, letting you pull and guide the ball in different ways to get the bricks you want. Paddle enhancements can also outfit your ship with weapons to take care of some of the peskier blocks that just won't jump in the way of your ball.
But not all pick-ups are enhancements. There are several pick-ups that bring your ball and paddle either back to normal, or in a worse condition. There is one that shrinks your paddle's width, one that speeds up the balls, and even one that returns your ball to normal (for when you have the large and/or explosive ball).