You can unlock a Secret called 'FPS Mode' then enable it in the secrets menu in Shadow Man Remastered.
This secret allows you to play through the entire game through a first person camera.
In order to find the secret, you must first get the Engineer's Key from the Asylum: Gateway and take a trolley to the Experimentation Rooms. Once you find your way into the coal corridors of the Experimentation Rooms, you'll come across a large fan that sucks you towards it. You need to progress through the level further until you reach a point where you are on the other side of the fan. Once you're there, you need to walk towards it, pushing against the fan's air resistance until you're right up against it, where you'll unlock your next secret.