The gameplay is more or less identical to the SNES Yoshi's Island
. When Yoshi
takes damage, the baby you're currently carrying will start to float away in a bubble and you have to save him before a timer gets to zero. If you don't, you will lose a life and start the level over unless you hit a middle ring to keep going. In the original game the only baby you carried around was baby Mario, throughout this game however, you pick up baby versions of Wario, Peach, Donkey Kong and Bowser(with Mario). They all have unique abilities, that aid in the puzzles throughout the game's levels. The game makes extensive use of the dual screen design, part of the world is shown on the bottom screen, the other part is shown on the top screen. Yoshi's Island DS does not use touch screen throughout most of the game.
Yoshi can jump, run, eat enemies and then use them as weapons by transforming them into eggs then throwing them, and even transform into various Yoshi-vehicles that aid Yoshi in progressing through the levels in the game.
There are five worlds in the game, each with its own theme. Each world gets progressively harder, with trickier platforming and harder puzzles. There are secret('extra') levels in the game, two for each of the five worlds. One set is unlocked by completing the game, the other set is unlocked by completing each level in all five of the worlds with a perfect score. You achieve a perfect score by collecting all of the flowers, stars and red coins throughout the level. These secret levels are extremely tough and combine many of the platforming attributes from the world the secret levels are attached to. (there's two secret levels for every world.)
Another addition to the game is a series of five minigames you can access from the main menu, after you collect special coins called "character coins." You collect these coins throughout the game's five worlds, once you collect all the coins from any world, a new minigame is unlocked.