Here is the full list of all 12 Rolling Hills: Make Sushi, Make Friends achievements.
Recycle 100 Soda Cans.
Learn every recipe.
Complete the second ritual and meet Yeti.
Complete the third ritual and meet Oni.
Complete the first ritual and meet Kappa.
Collect 10 hats.
Collect 25 different pieces of furniture.
Reach Friendship Lv. 1 with 5 people.
Complete 250 orders.
Complete 100 orders.
Complete 25 orders.
Save Rolling Hills.