Here is the full list of all 34 Fall Guys achievements. It takes around 50-60 hours to unlock all of the achievements on Windows.
Win an Episode as part of a party of 3 or more players
Reach lvl 40 fame during a season
Equip a legendary Body Colour, Pattern, Upper and Lower Costume piece
Qualify from a team game with a score of 1
Qualify from 500 rounds
Unlock 50 cosmetic items from the store
Win 20 Episodes
Clock up 1 hour total time falling
Win 5 Episodes in a row
Get first place in a racing round 20 times
Fall for at least 3 seconds before landing on your head
Reach lvl 25 fame during a season
Win 7 Episodes
Win an Episode with a custom Celebration equipped
Get first place in a racing round 5 times
Qualify from 100 rounds
Win your first Episode
Reach terminal velocity
Reach lvl 10 fame during a season
Qualify after a round goes to overtime
Equip a rare or legendary Body Colour, Pattern, Upper and Lower Costume piece
Equip an uncommon or better Body Colour, Pattern, Upper and Lower Costume piece
Bump into other Fall Guys 1000 times in total
Get first place in a racing round
Perform an emote just before coming first in a race round
Qualify from a racing round despite falling over more than 10 times
Qualify from a round without falling over even once
Knock someone over
Share a hug with a Fall Guy
Bump into 3 people while rolling on the ground before getting up
Qualify from your first round
Unlock 10 cosmetic items from the store
Equip your first cosmetic item
Equip your first legendary customization item