Completionist

Open the Clothing Store

At least one man and one woman on the island, and 5 problems solved.

Open the Hat Shop

Two men and two women, and 10 problems solved.

Open the Rankings Board

Five islanders, and 15 problems solved.

Open the Compatibility Tester

Two men and two women, and 30 problems solved.

Open the Photo Studio

Ten islanders, and 50 problems solved.

Open the Interiors Shop

Save more than $200.

Open the Pawn Shop

Collect five different treasures.

Open the Concert Hall

Give a song to an islander who has just leveled up.

Open the Observation Tower

Give a gift to an islander who has just leveled up.

Open the Campground

Send a grown-up child off traveling.

Fill the island with 100 Miis

The Mii Apartments hold 100 at most.