Evan's Remains

Missable.

You can do this on any puzzle. When you're in front of any Monolith puzzle, stand idle in front of it for at least 15 minutes. There's a chance this will unlock naturally if you're playing the game legitimately (not skipping the puzzles) but none of the puzzles are too overly complicated to solve, so it's best to do this on your own accord.

As soon as you hit the 15 minute mark, the trophy will unlock.