Here is the full list of all 30 Nightmares from the Deep 2: The Siren's Call achievements worth 1,000 gamerscore.
Completed the bonus adventure.
Completed the game.
Completed the game on expert difficulty
Got to the contents of Davy Jones' chest.
Gathered a twelve golden fish tokens.
Finished all the puzzles without skipping
Found all hidden octopi.
Found all morphing parrots.
Got to the top of the lighthouse and saw what's underneath.
Enabled your ally to return to work.
Prepared a spiked coffee.
Finished 10 Hidden-Object Scenes in a row without using any hints.
Found your way inside the lighthouse.
Fixed the radio.
Found 4 Hidden Objects within 4 seconds.
Found all secret sea horses.
Entered the shipwreck cemetery.
Finished a Hidden-Object Scene in less than 1 minute.
Finished any Hidden-Object Scene with less than 3 mistakes.
Saved your ally from a tight spot.
Found a direct way to get behind the closed gates.
Finished 5 puzzles in a row without skipping.
Visited a local bar.
Finished a puzzle in less than 1 minute.
Witnessed the devastating attack of the sea monster.
Arrived on the pier.
Finish all Hidden-Object Scenes.
Finish a game of Mahjong in less than 1 minute.
Finish half of all the games of Mahjong.
Finish all the games of Mahjong.