I'm just not good at finding things. Went thrice over the beautiful tropical jungle island, for half an hour, and found only two memories and a fake one. The first one was easy to find, and with the clue I found the third. I encountered several places which would have been a great hiding place for a memory but there were none.
The idea with the fog is interesting, and the story has potential but searching the whole main island (and some smaller ones) for objects not connected to any prominent feature can become a chore even if you like open worlds as much as me. So I think the environment design was great but the level design was not. I know you are giving clues over time but even then - the size of the level is very large for the task. And many players don't want to wait too long for progression.
I have been accused of making too large levels myself ;-) but I had a detection mechanic which shows when the player is near interesting things. You could implement similar elements.
There was no UI. I would have liked a hint for a button to recall the intro page.
The game is in desperate need of sound: ambient (it's a JUNGLE), background music for the mood and SFX for taking a memory.
Playing with keyboard and mouse, the controls worked flawlessly.