Here is the full list of all 16 PLANET ALPHA achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
What lies beyond
Like a big family
It was never meant to happen
Collecting the fourth artifact
Don't fight the flow
Another time another opportunity
Curiosity is key
Collecting the third artifact
Can't compete with the trees
Collecting the second artifact
Downwards is the new upwards
Slipping through the cracks
Falling is not an option
Collecting the first artifact
How did they get it up there
Resting by the pond