Here is the full list of all 14 Pikuniku achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Kick Mr. Sunshine into space
Found every insect
Get some arms
Collected 70 coins
100% against the dance king
Escaped from Toastopia
No respect for Sam's potteries
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