Here is the full list of all 15 Beyond the Invisible: Darkness Came achievements.
Beat the game in Expert mode
Beat the game in Advanced mode
Finish five HOPs without using the Hint
Finish a Hidden Objects Scene in less than a minute
Beat the game in Casual mode
Finish three HOPs without using the Hint
Solve 10 puzzles without Skipping
Solve five Puzzles without Skipping
Finish a HOP without using the Hint
Find 10 items in 10 seconds
Find five items in five seconds
Find three items in three seconds.
Finish the tutorial
Solve a Puzzle in less than a minute
Solve a Puzzle without Skipping