This is an excellent pinball game. You get two different tables (red and blue) and a nice variety of targets, lanes, and other special shots.
The small size of the Gameboy screen is compensated for by having the pinball table be twice as high as the screen. The screen automatically moves from one half to the other of the table in order to follow the ball. I found this a little bit confusing at first, but very quickly adapted to it. The tables are designed so that this doesn't really get in the way of gameplay. The ability to "nudge" or shake the table to change where the ball is going is well done; you'll need to build up skill in when and how much to nudge if you want to get good at the game.
I was dubious about the rumble feature, but I found it to be kind of fun - you feel many of the bounces that the ball makes with your gameboy buzzing and vibrating in your hand. I didn't find that it distracted me from the game; if you don't like it or aren't in the mood, just remove the battery from the game cartridge.
And, oh, yeah, there's Pokemon in the game! If you don't know anything about Pokemon, don't worry, knowledge of pokemon is not important for playing the game. If you are into Pokemon, during the game you get chances to capture various different ones; over time, you build up a collection of them. You don't really use the collection for anything, but it is fun to keep track of which you do and don't have, and it's exciting when you manage to capture a rare one.