Here is the full list of all 17 The Gunk achievements. It takes around 4-5 hours to unlock all of the achievements on Windows.
Scanned fifteen objects
Landed the Dust Bunny
Cleared the first Gunk
Set up Camp
Cleared the Gunk Tower
Defeated the Gunk Beast
Found the Garden
Got out of the Wasteland
Saved the day
Installed five upgrades
Installed all upgrades
Filled the encyclopedia
Threw one on another
Grabbed an unaware Gunk Spitter
Make one charge off a cliff
Made one charge into another
Blasted three to smithereens