Here is the full list of all 20 GNOG achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Test the astronaut for space sickness
Experiment in the studio
Discover what lurks below
Leave no trace
Keep the kitchen clean
Watch what you eat
Daydream at the blackboard
Finish the game
Complete LAB-O
Unlock every level
Complete LOG
Leave no worm behind
Complete VORT-X
Complete SUB-01
Complete HOM-3
Complete CANDY
Complete EATER
Complete PURP-L
Complete FRG-Y
Please don't bother the amphibians