Here is the full list of all 11 A Day in the Woods achievements.
Get 3 stars on the first 15 levels
Complete Level 1
Play a game in the Halloween theme
Change the theme of your game bard
Customize your sprite
Play a game in the Chrismas theme
Get 3 stars on all 60 levels.
3 star any level with a berry bush below the crowning par
Feed 20 bunnies to giant spiders
Complete A Day in the Woods