Here is the full list of all 22 United Penguin Kingdom: Huddle up achievements.
Build an Ocean Garbage Collector
Reach a population of 15 penguins
Build a Snow Block Maker
Complete the third tutorial
Build a School
Build a Temple
Build an Ice Rink
Build a Carousel
Build a Vase
Complete the second tutorial
Build a Herbs Collector
Build a Basic Cooler
Build a Food Stand
Build a Trawling Dock
Complete the first tutorial
Build a Newcomer Ramp
Build a Science Hub
Complete a year in the penguin kingdom
Build a Fishing Dock
Build a Village Hall
Request help from the king
Make a call for your first huddle-up!