Here is the full list of all 14 Pikuniku achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Collected 70 coins
Found every insect
Kick Mr. Sunshine into space
No respect for Sam's potteries
Get some arms
Escaped from Toastopia
100% against the dance king
Found every trophy
Kick your friends 50 times during a single level
Finish a coop level in less than 3 minutes
3 baskick wins in a row
3 baskick loss in a row
Make an artistic statement
999