It also features the first appearance of Mario's Dinosaur Friend Yoshi. Mario, Luigi, and Yoshi have to save Princess Peach Toadstool and Yoshi's friends from King Bowser Koopa and his Koopalings. The gameplay action is sidescrolling as in previous Mario games, but adds some two-dimensional scrolling and takes advantage of the Super Nintendo's 16-bit graphics and stereo audio. The game consists of a journey through levels in seven worlds: Yoshi's Island, Donut Plains, Vanilla Dome, Cookie Mountain, Forest of Illusion, Chocolate Island, and the Valley of Bowser. There are also two secret worlds, the Star Road and Special Zone which can be accessed by completing secondary goals in specific levels.
The music was composed by Koji Kondo.