Here is the full list of all 30 Nightmares from the Deep 2: The Siren's Call achievements worth 1,000 gamerscore.
Finish a puzzle in less than 1 minute.
Finish 5 puzzles in a row without skipping.
Finish all the puzzles without skipping.
Finish a Hidden-Object Scene in less than 1 minute.
Finish 10 Hidden-Object Scenes in a row without using any hints.
Finish all Hidden-Object Scenes.
Find 4 Hidden Objects within 4 seconds.
Finish any Hidden Object scene with less than 3 mistakes.
Finish a game of Mahjong in less than 1 minute.
Finish half of all the games of Mahjong.
Finish all the games of Mahjong.
Find all secret sea horses.
Find all morphing parrots.
Find all hidden octopi.
Arrive on the pier.
Witness the devastating attack of the sea monster.
Visit local bar.
Gather twelve golden fish tokens.
Find a direct way to get behind the closed gates.
Save your ally from a tight spot.
Enter the shipwreck cemetery.
Fix the radio.
Find your way inside the lighthouse.
Enable your ally to return to work.
Prepare a spiked coffee.
Get to the top of the lighthouse and see what's underneath.
Get to the contents of Davy Jones' chest.
Complete the game.
Complete the game on expert difficulty.
Complete the bonus adventure.