Here is the full list of all 43 SWEATER OK achievements.
Destroy 50 snake parts
Collect 100 000 points in a single session
Survive for 5 minutes
Destroy 5 snakes simultaneously
Destroy 10 snakes in a single session
Allow snakes to eat 100 stars
Collect 100 stars
Allow snake to kill you during a speed boost
Collect less than 100 points in a single session
Collect 50 000 points in a single session
Collect 3 stars during the slow motion
Destroy 10 snake parts
Gain a 10x multiplier
Smash 10 eggs
Allow snake to eat a black mark
Collect 10 stars in a single session
Allow snake to eat a speed boost
Survive for 1 minute
Collect 50 stars in a single session
Collect 100 stars in a single session
Collect 500 stars
Collect 1 000 stars
Collect 5 000 stars
Destroy 100 snake parts
Collect 500 000 points in a single session
Collect 1 000 000 points
Collect 5 000 000 points
Collect 10 000 000 points
Allow snake to split into 20 parts and kill them
Allow 10 snakes to appear on a level
Smash 100 eggs
Smash 1 000 eggs
Smash 228 eggs in a single session
Allow snakes to eat 250 stars
Allow snakes to eat 500 stars
Die 666 times
Survive for 10 minutes
Survive for 15 minutes
Survive for 30 minutes
Survive for 45 minutes
Survive for 60 minutes
Fail to collect the black mark (you need to be closer than 3 tiles from it)
Play 69 times in a row