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
Beat the game in Casual mode
Solve 10 puzzles without Skipping
Finish three HOPs without using the Hint
Solve five Puzzles without Skipping
Finish a Hidden Objects Scene in less than a minute
Finish the tutorial
Find 10 items in 10 seconds
Finish a HOP without using the Hint
Find five items in five seconds
Find three items in three seconds.
Solve a Puzzle in less than a minute
Solve a Puzzle without Skipping