I have this idea You have X playable maps so why not make it like in one of frankies videos so that you can travel across them with a plane or some portal like minecraft. So lets say I start a private server just with some friends no pvp and I want a goal .. lets say repair a plane that has differents parts (marked) all over the map maybe with objectives (left 4 dead style) you fix the plane and get to the second map and so on.. And if you die in the second map you spawn in the first.. ( this might be hardcore I know :) and also not possible because you can only have one map up at a time..) Also each map has its own dificulty, harder every time.. And on the final map maybe a mission where theres the source for the plague.. and maybe a bossfight.. Thanks
