Here is the full list of all 20 ISOLAND3: Dust of the Universe achievements.
Throw the crab on the beach back into the sea
Find the legendary giant fish in the sea
Input the secret code into the computer
Find the moss that's different
Wait for the last flower to bloom
Rock the signpost
Discover the mural on the wall
Free the bug from the vine
Feed the bird once
Find the fourth door in the shrine
Solve the code on the spaceship
Discover the big bird outside the window
Return to the past aboard the spaceship
Grab the three childhood objects
Watch the movie once
Fix the robot
Find the plane in the child's study room
Find the lute
Watch the spaceship land
Find every flower.