Here is the full list of all 12 Good Goliath achievements.
Collect every set of special hands for the giant
Defeat the king of the castle
Defeat the pirate captain and monster of the seas
Defeat the lord of the underworld
Earn a gold medal in the Peasantville level
Earn a gold medal in the Royal Arena level
Earn a gold medal in the Cabeza Cove level
Earn a gold medal in the Ship of Plunder level
Earn a gold medal in the River Styx level
Earn a gold medal in the Gates of Hurl level
Collect a new set of hands for the giant
Collect 5 new sets of hands for the giant