Full list of all 11 Time Mysteries 2: The Ancient Spectres achievements. It takes around 4-5 hours to unlock all of the achievements on Windows.
Unlocked all the other Achievements.
Finish the bonus chapter
Complete the game
Finish all Mini-Games without skipping.
Finish all Hidden Object Puzzles without using hints.
Finish 15 Hidden Object Puzzles in a row without using hints.
Finish any Mini-Game in less than 1 minute.
Finish any Hidden Object Puzzle in less than 1 minute.
Finish 4 Mini-Games in a row without skipping.
Finish any Hidden Object Puzzle with less than 4 mis-clicks.
Find 3 hidden-objects within 3 seconds.