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.
Grabbed an unaware Gunk Spitter
Installed all upgrades
Filled the encyclopedia
Blasted three to smithereens
Made one charge into another
Saved the day
Got out of the Wasteland
Found the Garden
Defeated the Gunk Beast
Cleared the Gunk Tower
Make one charge off a cliff
Installed five upgrades
Set up Camp
Threw one on another
Scanned fifteen objects
Landed the Dust Bunny
Cleared the first Gunk