Here is the full list of all 15 Seasons With Furry achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Complete the level on a hard level of difficulty
Complete the level at medium level of difficulty
Complete level 12
Complete level 11
Complete level 10
Complete level 9
Complete level 8
Complete level 7
Complete level 6
Complete level 5
Complete level 4
Complete level 3
Complete level 2
Complete the level on easy difficulty level
Complete level 1