Summary: Do not purchase this very amazing game USED. Steam requires to be installed and if the game code has been used, you will not be able to install in any way or form. I purchased one used and steam told me the only thing I could do was refund the product. So if you don't want the hassle of possibly having to return this awesome game, DO NOT BUY USED.
Summary: Just make sure you look at the fine print. I had no problems with the seller just the company I had to go through to activate the game.STEAM, they would not let me activate the game with a used key code. So watch out. I really wanted to play this game but I guess I'll have to wait.