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