The premise of the game is identical to Super Mario Bros.: Bowser has abducted Princess Peach (Toadstool) and is holding her captive in one of his castles. Either Mario or Luigi must navigate through the Mushroom Kingdom, overcome Bowser's henchmen, and rescue the Princess. The game uses the same game engine as its predecessor and is quite similar in visual style. It is intended to challenge players who have mastered the original Super Mario Bros.

NOTE: The original SMB2j would add stars to the title screen every time you beat the game up to 8 stars. After 8 stars you can hold (A and push Start) to go to world A-1. I hacked the game so these stars are always on the title screen. You can use the button sequence on the title screen at anytime for the bonus levels.