This achievement requires you to complete the game on advanced mode, but completing the game on advanced mode can be a little difficult. So what you have to do is to complete the game on regular mode. After the last cutscene you will be back to main menu. Now don't click on new game, click play instead. You will be back in the room with Matt. Go to options(move mouse to the top left of the screen), change the mode to advanced. Go to the vampire, use the shield on him. Skip the cutscene and Done!