In which Kirby game can Kirby use a mech suit?

Kirby can use a mech suit in Kirby: Planet Robobot, the 2016 Nintendo 3DS platform game.

The suit is called the Robobot Armor, and it gives Kirby a powerful new way to fight and explore. The armor can smash obstacles, lift heavy objects, defeat large enemies, and scan enemies to gain versions of their abilities. This makes the mech more than a temporary vehicle: it is a central gameplay system built around adapting Kirby's familiar powers to a larger mechanical body.

The story begins when the Haltmann Works Company mechanizes Planet Popstar and starts extracting its resources. Kirby acquires the Robobot Armor while battling the corporation and eventually uses it in the conflict involving President Haltmann and the supercomputer Star Dream. A common mix-up is choosing Kirby: Triple Deluxe, the game's predecessor; it also uses layered 3D environments, but it does not introduce Kirby's playable mech armor.