Aliens versus Humans: Missions is a new standalone game. It accomplishes a couple of things. First, it is free to play the first 5 missions. If you like the game, you can choose to purchase the remaining 20 missions. Second, we added free PvP. This means you and a friend can play against each other for free. There are 3 different types of PvP - you can play classic PvP, Capture the Flag or Scramble PvP. A lot of people have asked us to provide a "lite" version of Aliens versus Humans. Some just aren't sure and don't want to spend the money on a title they just might not like. But we didn't just want to add a "lite" version so in addition, we added PvP.