Here is the full list of all 27 The Cave achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Helped the Knight obtain Excalibur.
Reached the bottom of The Cave.
Got everyone out of The Cave without dying once.
Saw a postcard stolen from the Gift Shop.
Remembered it's wrong to steal.
Everyone reached the bottom.
Saw the good in everyone.
Saw the darkness in all our hearts.
Collector of forgotten dreams.
Sacrificed oneself for ultimate flavor.
Where did the King go anyway?
The scale reveals a baleful figure.
3 die by the Miner's hand.
Pantomimed an ancient hieroglyph.
Watched Mummy and Daddy's furniture get broken all to bits.
Made all three characters smell like a dinosaur at once.
Recorded and played back the elevator music from the Zoo food court.
Slipped, where wet.
Broke bridges.
Food-based destruction.
Peered into everyone's fate.
Enabled the Hillbilly to burn down the Carnival.
Came ever-so-close to recovering the Sarcophagus.
Stood by and watched as the Twins murdered their parents.
Served as an accessory to the Time Traveler's murder of her enemy's ancestor.
Shared in the blame for the Scientist's act of mass murder.
Played some dubious role in the Monk's murder of his Master.