Island Rhythms! Achievement in Bluey: The Videogame

The Magic Xylophone minigame unlocks as part of the story, during the fourth episode. 

This game requires you to press  near each family member while they run around. This is quite easy to do. Just mash  as you run around near each family member, and you'll likely complete the minigame in under ten seconds, plenty of time to unlock this achievement.