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 worm behind
Experiment in the studio
Watch what you eat
Keep the kitchen clean
Please don't bother the amphibians
Finish the game
Complete HOM-3
Leave no trace
Complete LAB-O
Daydream at the blackboard
Unlock every level
Complete CANDY
Complete LOG
Complete EATER
Complete VORT-X
Test the astronaut for space sickness
Complete PURP-L
Complete SUB-01
Discover what lurks below
Complete FRG-Y