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
Share a puzzle
Complete a puzzle from the Workshop
Lob a Pig Barf using an Inhale Whale
Complete a puzzle without using 2 items
Complete a puzzle in every world
Get 100 Treats
Move a Treat using an Ejection Cart
Get 50 Treats
Complete all puzzles in any world
Unlock your first Puzzle Maker item
Complete a puzzle without using all the items
Unlock your first bonus puzzle