And by Game Boy I mean a set of 20 LCD tiger electronic style mini games.
According to khinsider, the news came from a reveal at a Kingdom Hearts Union X event, the Kingdom Hearts Mobile game that was released in North America in early 2016. The video shows Sora, Donald and Goofy in twilight town with NPC characters Hayner, Pence and Olette as they huddle around the game console that will play said games.
Kingdom Hearts 3 is the long awaited third installment in the Square Enix Franchise first announced at E3 2013. You can start playing these mini games when the full games is released sometime this year.