Here is the full list of all 11 Enigmatis: The Ghosts of Maple Creek achievements worth 1,000 gamerscore.
Finished the bonus chapter.
Finished game on normal difficulty
Finished game on expert difficulty
Finished all Hidden Object Puzzles without using hints.
Finished all Mini-Games without skipping.
Finished 6 Mini-Games in a row without skipping.
Finished 7 Hidden Object Puzzles in a row without using hints.
Finished Hidden Object Puzzle in less than 1 minute.
Finished Mini-Game in less than 1 minute.
Finished Hidden Object Puzzle with less than 4 mistakes.
Found 3 hidden-objects within 3 seconds.