Here is the full list of all 27 The Cave achievements worth 400 gamerscore. It takes around 12-15 hours to unlock all of the achievements on Xbox 360.
Spied a King, eaten by a Dragon.
Saw a postcard returned to the Gift Shop.
Played some dubious role in the Monk's murder of his Master.
Got the bridge inside the temple to collapse.
Served as an accessory to the Time Traveler's murder of her enemy's ancestor.
All three characters killed by one Miner's dynamite.
Enabled the Hillbilly to burn down the Carnival.
Saw a postcard stolen from the Gift Shop.
Reached the bottom of The Cave.
Shared in the blame for the Scientist's act of mass murder.
Stood by and watched as the Twins murdered their parents.
Watched Mummy and Daddy's furniture get broken all to bits.
Helped the Knight obtain Excalibur.
Nobody died.
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.
The scale reveals a baleful figure.
Pantomimed an ancient hieroglyph.
Everyone is gross.
Captured crusty melodies.
Slipped, where wet.
Food-based destruction.
Peered into everyone's fate.
Came ever-so-close to recovering the Sarcophagus.