For anyone who owned an NES or played SMB in the arcades, this is a must buy. It is exactly the way it was back then. It has the "Lost Levels" and special "Toy Box" features. Gotta love that. The one gripe I have is that, because it is an exact port of the NES version, sometimes you have to scroll the screen (by using up or down) to see the picture. I'll admit that the first few times through, I wasted a few lives accidentally hitting Koopa Troopa's I didn't see, and Lakitu was usually above the screen dropping Spiny's, so I didn't know where he was unless I scrolled up. Other than that, it's an awesome game. A must have for anyone who had an NES or, like me, wasted quarters at the arcade on SMB.

PROS:
-THE ENTIRE CLASSIC GAME IS HERE. All 32 levels that made video gaming fun back in 1985 have been restored, right down to the last block. Also, the 32 extra "star" courses have been restored. If you remember the original game, you'll remember that these stages are the same as the normal ones, but they have been altered to be more difficult in many small ways (Buzzy Beetles replace Koopa Troopas, platforms are smaller, etc.) That's 64 levels!
-THE ENTIRE ORIGINAL "SUPER MARIO BROS. 2" GAME IS HERE. The original Super Mario Bros. 2, known to American gamers as The Lost Levels, can be found on this cartridge. If you never got Super Mario All-Stars but want to own The Lost Levels in some shape or form, just buy this game!
-NEW MODES. There is now a mode where you must search each level for five hidden red coins, a Yoshi egg, and at the same time you must try to get a high score. Also, there is a mode where you must race Boo to the end of a stage.
-BONUS MATERIAL. Every time you complete a world in the original game, you'll unlock bonus material that you can print out with your Game Boy Printer (if you have one.) There are other little bonuses, too.
-YOU CAN SAVE YOUR GAME. Unlike the original game, in which you had to start over every time you played, this one lets you save on any level!
-YOU CAN BE MARIO OR LUIGI. Both Bros. are playable in this game. Mario plays true to his 1985 counterpart, while Luigi is a little tougher to control but jumps higher. Diversity like this can only improve a game.
-IT'S CHALLENGING. Even by today's standards, this is a tough platformer. Don't expect to just pick this up and win quickly because it's an old game; you'll be surprised by the difficulty.
-EXCELLENT MUSIC AND SOUND EFFECTS. Even back in 1985, Koji Kondo had the ability to create excellent video game music - something he's still doing to this day. The sound effects are also some of the most memorable ever heard in a video game.
-MANY CLASSIC MARIO CHARACTERS ARE INTRODUCED HERE. Princess Peach/Toadstool, Bowser, Toad, Goomba, Koopa Troopa, Koopa Paratroopa, Hammer Bro, Bullet Bill, Buzzy Beetle, Piranha Plant, Podoboo, and a few others all made their debut here.

CONS:
-YOU CAN'T SEE THE WHOLE SCREEN. The Game Boy Color's screen can't compare to the size of a TV, so you have a good deal less room to manuver than you did in the original game. Having to press up and down to see different parts of the screen is annoying.
-NOT AS CHALLENGING AS THE ORIGINAL. Being able to save your progress makes the game much easier, and thus a good deal of the challenge is lost right there.
-NOT AS NEAT IF YOU DON'T HAVE A GAME BOY PRINTER. If you don't have a Game Boy Printer, you won't be able to print out many of the bonus features. That bites, since VERY FEW gamers have a Game Boy Printer.
-"SUPER MARIO BROS. 2" HAS HAD BACKGROUND ALTERATIONS. For some odd reason, all of the Super Mario Bros. 2 stages have been altered to look more like the levels in the original game. Why? They should have left the game as it was, so that gamers could play the game in all its uncut, original glory.
-STORYLINE IS WEAK. This was the first in a long line of games to use the "rescue Princess Peach/Toadstool" storyline, which would be beaten to death in other Mario games. In a way, you might say this game created a monster.
-NINTENDO SHOULD HAVE WAITED AND REISSUED THIS ON THE GAME BOY ADVANCE. Many old Mario games have gotten new life on the Game Boy Advance. Why did they have to rerelease this, the first game in the series, on the inferior Game Boy Color?

OVERALL:
You may be wondering whether or not you should buy this game if you already have the original. I say yes. This game has been available for quite some time on a number of consoles, but this is the first time it has ever been available as a portable game. The bonus features are reason enough to purchase this version of the game, believe it or not. Final verdict? If you've got a Game Boy, this is a must-buy.