Increasing play count might involve editting a hex value in the game's .exe. That's how it was done in the first game. Unsure how to go about doing that myself. This is a guide to that for the first game, maybe someone could figure it out. Doesn't seem like it should be all that complicated, unless there's other issues that stem from more than 4 players (e.g., UI stuff).
http://steamcommunity.com/sharedfiles/filedetails/?id=548760493
