By third part do you mean the veil shield? Because I have that at just over 2 and a half hours in :/ I have been rushing to complete the game asapI have a habit of giving up on single player games before I finish them
Just got that bit, but I had to drop the difficulty level to "wussie" temporarily to get through the last part of Hospital though.
Of course all that happens when you get the last piece is the enemies level up (or more of them).
Still find it really irritating having to fight your way between missions.