Here is the full list of all 46 OCO achievements.
jump 1200 times
complete 5 levels in perfect taps
complete 5 levels in perfect time
collect 3000 bits
unlock a special platform in 'create'
unlock a background colour in 'create'
play an 'explore' level
play for 1 hour
rate OCO
share your score
complete a level in over 100 taps
complete 20 levels in perfect taps
complete 20 levels in perfect time
complete 3 worlds
explode 100 times
play for 5 hours
watch 5 solutions
fall off the bottom of the screen
complete a level in over 500 taps
complete 100 levels in perfect taps
complete 100 levels in perfect time
complete a world in perfect taps
complete a world in perfect time
draw 100000 segments in 'create'
complete 20 daily challenges in a row
complete a world in perfect taps and time
explode 10000 times
jump 100000 times
complete 5 levels in fewer than perfect taps
complete 5 levels in faster than perfect time
collect 100000 bits
receive 1000 likes
complete 5 worlds in perfect taps and time
play for 100 hours
share your score 50 times
complete an ultimate level without watching the solution
complete 30 ultimate levels
complete 100 extreme levels
acquire all achievements
complete explore world 9 in perfect taps and time
complete explore world 10-3
complete all speedruns
complete all marathons
complete explore world 13 in perfect taps and time
complete explore world 15 in perfect taps and time
complete explore world 14-1