True Fear: Forsaken Souls - Part 1

Self-explanatory – when you start a new game, choose Expert difficulty, then finish the main game.

This can actually be cheesed, if you wish. While I was writing the walkthrough I played the game on casual, then when I was in the final room of the game, I went into the game's options and changed the difficulty to Expert. I finished the game, and this trophy unlocked.

The benefit to playing on Casual is that interactable locations will sparkle. You will also have the hint option available, but you shouldn't be using it! I have heard reports that some puzzles are shorter on Casual, but this made no difference in the puzzles I identified as being the ones that have locked players out of How do you do it III.