yeah the map is pretty useless, it's sort of a pseudo-3D render that is just impossible to follow.
maybe you know this, but if you hold CTRL, you project a blue beam on the floor that shows you where to go to complete the next objective. i use that instead of the map most of the time. i just check the map if i see an unlocked door that the beam doesn't lead me in to - i check to see where it goes before i venture in and get ripped in half
i'm only on chapter 2, i can't play for too long at once, otherwise i just get too wound-up. it's an intense game!