Here is the full list of all 14 Eets Munchies achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
Complete all puzzles
Get all the Treats
Get 100 Treats
Complete a puzzle without using 2 items
Lob a Pig Barf using an Inhale Whale
Move a Treat using an Ejection Cart
Complete a puzzle from the Workshop
Get 50 Treats
Complete a puzzle in every world
Complete a puzzle without using all the items
Share a puzzle
Complete all puzzles in any world
Unlock your first Puzzle Maker item
Unlock your first bonus puzzle