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.
Collecting the first artifact
It was never meant to happen
Like a big family
Can't compete with the trees
Falling is not an option
Don't fight the flow
Collecting the fourth artifact
Another time another opportunity
Curiosity is key
Collecting the second artifact
Collecting the third artifact
What lies beyond
Downwards is the new upwards
Slipping through the cracks
How did they get it up there
Resting by the pond