Here is the full list of all 24 Adventure Time: Finn and Jake Investigations achievements.
Correctly guess the Grayble theme.
Put Finn's favorite song back onto the record album.
Locate and interact with 15 snails.
Convince Finn's friends to join the band.
Gather the equipment needed to re-record Finn's record.
Listen to all of the radio broadcasts in the Tree House bedroom.
Find the last of the artifacts and seal Billy's Cave.
Escape from the dungeon below Billy's Cave.
Find out why the Fire Kingdom's flames are going out.
Defeat Magic Man's latest jerky plan.
Find the missing Sound Sword.
Find a cure for the dancing epidemic.
Put the king back in charge of his kingdom.
Fix all of the noble deeds that were done incorrectly.
Say hello to the new character in Ooo.
Use the telescope in the boat to look at three different kingdoms.
Find the hairy beast that has been wreaking havoc.
Defeat the wizards and free the kidnapped Candy People.
Find a way to get into the wizard "party."
Dial 10 wrong numbers on the pay phone.
Free Abracadaniel from jail.
Use all four Jake combat forms at least once in the game.
Perform a 15-hit combo in combat without being hit.
Visit every area in and around the tree house.