Yoshi's Island Wii U is the direct sequel to Yoshi's New Island, an indirect follow-up to Yoshi's Island DS, and chronologically the fifth video game in the Mario series. Compared to its predecessor, this game has more levels, remastered graphics, new babies, and a whole new adventure. In this game, Kamek and the Toadies have once again kidnapped all the babies in the world, including Baby Luigi. Yoshi, Baby Mario, Baby Peach, and the Stork team up and attempt to save the babies. Baby Daisy and Baby Waluigi debut in this game. This is the fourth Yoshi's Island game since the original which was released in 1995. The prequel, Yoshi's New Island for Nintendo 3DS, was released in March 2014.
Gameplay mainly revolves around adventure mode, similarly played out as the original. Throughout the eight unique worlds, a different colored Yoshi takes on one out of eight levels, with a mini-boss in Level 4 and a boss in Level 8 of each world. Enemies, items, coins, and other collectibles litter the levels. Some items count toward a score of 100, which is then displayed in the level select screen. If every level in a world has 100, one level, the extra level, is unlocked.
When a Yoshi is hit by an enemy, the baby is knocked loose from his back crying, and the star power - the source of the protective bubble that keeps the Toadies from taking the baby - goes down by one star per second. If that number goes down to zero, Toadies take away the baby and a life is lost. Yoshi, however, still has a small amount of time to recover the baby even after the Toadies have grabbed. Yoshi can rescue the baby by touching the bubble with its body or its tongue. If Yoshi hits the bubble with an egg, the bubble gets knocked down, making the baby easier to reach. The star power starts at ten in each level. If a baby is recovered with less than ten stars, the star power slowly reverts to ten. Additionally, groups of five stars can be found in Winged Clouds and crates, and goal rings give twenty additional star power, allowing the star power to max at thirty. Remaining star power also counts toward the score at the completion of the level.
Although Yoshi cannot be defeated in normal circumstances, he instantly loses a life if he touches spikes, lava, falls into endless pits, or gets crushed. The mode also features the Island Museum, which is accessible at any time. In this museum, all the enemies the Yoshis have defeated with Yoshi Eggs appear as exhibits.
There are several Minigames to be unlocked in Adventure Mode:
- Tulip Shooter - Yoshi must grab and spit enemies into a tulip.
- Flutter Challenge - Yoshi must try to flutter-jump as far as possible.
- Bouncy Maze - Yoshi must maneuver his way through a simple maze of Bouncies.
- Speed-Eater - Yoshi must try to swallow as many enemies as possible.
- Egg Toss - Yoshi must hit targets with eggs.
All minigames have a set time limit. Achieving a high score in any minigame awards Yoshi with an Extra Life. Harder versions of all the minigames can be unlocked by collecting all the Character Coins in a world.
Time Trial is unlocked once Adventure Mode has been beaten. It is similar to Adventure Mode, but, the player is timed. Yoshi has one hundred minutes to finish each level - even when the player presses the Start Button, the time continues. If the player collects Red Coins, Flowers, and Stars, time is added to the time taken to finish the level.
These enemies can also be seen in the Island Museum after they hit by eggs (even if the eggs do not defeat them) in the actual levels.
- Bandit: Bandits run into a Yoshi and stealing the baby it is carrying. It takes three jumps or a ground pound to defeat them.
- Beach Koopa: Beach Koopas walk into Yoshi. If they encounter an empty Koopa shell they will jump into it to become a Koopa.
- Bumpty: Bumpties bounce a Yoshi away if it touches him. They cannot be swallowed.
- Burt: Burts bounce into Yoshi. Burts cannot be eaten. A ground pound is required to defeat them.
- Crabble: Crabbles walk into Yoshi. They require three eggs to be defeated.
- Debull: Debulls charge into Yoshi. If they hit a wall they are briefly stunned. The only way to defeat one is to lead it off a cliff.
- Fleeper: Fleepers jump onto a Yoshi's back and steal the baby it is carrying.
- Green Glove: Green Gloves throw eggs at Yoshi. It takes three jumps or a ground pound to defeat them.
- Grinder: Grinders jump into a Yoshi and steal whatever baby it is carrying.
- Koopa: Koopas walk into Yoshi. They cannot be eaten when they are in their shell.
- Paratroopa: Paratroopas fly or walk into Yoshi. If they are jumped on they become normal Koopas.
- Slugger: Sluggers bat eggs at Yoshi. It takes three jumps or a ground pound to defeat them.
- Snap Jaw: Snap Jaws descend down vines to hit Yoshi.
- Tap-Tap: Tap-Taps walk into Yoshi. The pink ones will walk off platforms, but the grey ones will turn around when they reach the edge of one.