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.
Got everyone out of The Cave without dying once.
Saw every character's "good ending". (Player 1 only)
Unlocked all Cave Paintings. (Player 1 only)
Got a Xavetar fortune for every character. (Player 1 only)
Got the bridge inside the temple to collapse.
Pantomimed an ancient hieroglyph.
Got the Weight Guess scale to read 666.
Witnessed a hot dog cooked with the monster's breath.
Took all characters to the bottom of The Cave. (Player 1 only)
Saw every character's "bad ending". (Player 1 only)
Saw a postcard returned to the Gift Shop.
Shared in the blame for the Scientist's act of mass murder.
Saw someone slip off a ledge in the Missile Silo.
Made all three characters smell like a dinosaur at once.
Saw every Can of Corn in The Cave destroyed.
Recorded and played back the elevator music from the Zoo food court.
Stood by and watched as the Twins murdered their parents.
Watched Mummy and Daddy's furniture get broken all to bits.
Came ever-so-close to recovering the Sarcophagus.
Enabled the Hillbilly to burn down the Carnival.
Reached the bottom of The Cave.
Played some dubious role in the Monk's murder of his Master.
Served as an accessory to the Time Traveler's murder of her enemy's ancestor.
All three characters killed by one Miner's dynamite.
Spied a King, eaten by a Dragon.
Helped the Knight obtain Excalibur.
Saw a postcard stolen from the Gift Shop.