Here is the full list of all 12 Pocket Watch achievements.
Fix the boat.
Fail to save the island.
Go back in time.
Get a job.
Get into the secret hideout.
Find all 50 coins.
Find all 7 moons.
Beat the game.
Get the secret ending.
Fall into the volcano.
Beat the game in under 10 minutes.
Find all 5 gems.