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