Here is the full list of all 14 Co-op SNEK Online achievements.
Get to stage 5
Get to stage 10
Get to stage 15, Getting close!
Less than %5 people get this far, be happy :)
Get 5 Competative Points
Get 15 Competative Points
Get 30 Competative Points
Infinite Classic length 100
Infinite Classic length 125
Infinite Classic length 150
Infinite Classic length 200
Play a game with another person
Bump into things 100 times
Complete the deleted levels