I'm going to make a first-person shooter game that has both a singleplayer campaign and a traditional multiplayer mode. I'm thinking of adding co-op to the singleplayer mode, similar to what is done in Dying Light. I want to use a client as a listen server for co-op instead of spinning up a new dedicated server because that would help reduce costs. Does GameLift have any peer-to-peer tools, or do they only offer dedicated server multiplayer services?
