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