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.
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
Defeated the Gunk Beast
Found the Garden
Got out of the Wasteland
Saved the day
Installed all upgrades
Filled the encyclopedia
Grabbed an unaware Gunk Spitter
Made one charge into another
Blasted three to smithereens