Here is the full list of all 51 Hidden Memory - there are Nature achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
COMPLETE THE PUZZLE - 01
COMPLETE THE PUZZLE - 02
COMPLETE THE PUZZLE - 03
COMPLETE THE PUZZLE - 04
COMPLETE THE PUZZLE - 05
COMPLETE THE PUZZLE - 06
COMPLETE THE PUZZLE - 07
SOLVE IT DIFFERENT WAY - 07A
COMPLETE THE PUZZLE - 08
COMPLETE THE PUZZLE - 09
SOLVE IT DIFFERENT WAY - 09A
COMPLETE THE PUZZLE - 10
COMPLETE THE PUZZLE - 11
SOLVE IT DIFFERENT WAY - 11A
COMPLETE THE PUZZLE - 12
SOLVE IT DIFFERENT WAY - 12A
COMPLETE THE PUZZLE - 13
SOLVE IT DIFFERENT WAY - 13A
SOLVE IT DIFFERENT WAY - 13B
COMPLETE THE PUZZLE - 14
SOLVE IT DIFFERENT WAY - 14A
COMPLETE THE PUZZLE - 15
SOLVE IT DIFFERENT WAY - 15A
COMPLETE THE PUZZLE - 16
COMPLETE THE PUZZLE - 17
COMPLETE THE PUZZLE - 18
COMPLETE THE PUZZLE - 19
SOLVE IT DIFFERENT WAY - 19A
COMPLETE THE PUZZLE - 20
SOLVE IT DIFFERENT WAY - 20A
COMPLETE THE PUZZLE - 21
SOLVE IT DIFFERENT WAY - 21A
COMPLETE THE PUZZLE - 22
COMPLETE THE PUZZLE - 23
COMPLETE THE PUZZLE - 24
SOLVE IT DIFFERENT WAY - 24A
COMPLETE THE PUZZLE - 25
COMPLETE THE PUZZLE - 26
COMPLETE THE PUZZLE - 27
SOLVE IT DIFFERENT WAY - 27A
COMPLETE THE PUZZLE - 28
COMPLETE THE PUZZLE - 29
COMPLETE THE PUZZLE - 30
COMPLETE THE PUZZLE - 31
COMPLETE THE PUZZLE - 32
COMPLETE THE PUZZLE - 33
SOLVE IT DIFFERENT WAY - 33A
COMPLETE THE PUZZLE - 34
COMPLETE THE PUZZLE - 35
SOLVE IT DIFFERENT WAY - 35A
COMPLETE ALL PUZZLES