This was the first "Mario" game for the Game Boy, and I had fun playing it. It had some good points and some bad points, so I'll list the good points first.
The game is a typical "Mario" game, where you have to play through 4 worlds of 3 levels each, avoiding enemies and fighting a boss at the end of each world. You start the game with 3 lives, and you get an extra life whenever you collect 100 coins. You can also get a chance to continue when you've lost all your lives, but I'm not sure how.
As for the bad points, there is no save feature, the graphics are terrible, and for some weird reason the screen won't scroll left. I suppose these are just because the Game Boy is a very old system, but they are bad points nonetheless.
Overall, this game is very fun, and if you decide to get it, I hope you enjoy it.