Halo: Reach is a game in which you, an anonymous soldier, make your way through linear levels from a generally first person perspective. Your primary interaction with the world around you is through the barrel of a gun, which is handy because everything wants to kill you. Sometimes you come across men that want to kill things that want to kill you. This makes them your friends. You reach the end, credits roll, and then you head online to do much the same thing without the linearity.