Here is the full list of all 12 Abyss of Neptune achievements.
Complete the tutorial.
Get the harpoon gun.
Complete the Academics Wing.
Find 3 logs.
Find 6 logs.
Find all logs and complete the game.
Complete the game in under 30 minutes.
Complete the game without using any healing items.
Complete the game in easy mode.
Complete the game in normal mode.
Find the hidden room.
Complete the game in Hard Mode