Despite my best efforts, the Unreal Engine is simply not reverse-engineering friendly like Source is. This got me thinking though; can the game be tricked into accepting UPKs that aren't part of the base game? If you setup the camera and npc pawns in the same way, could the map list be changed to accept a new UPK? I don't know what if any properties are associated with the spawning of soldiers and aliens, it is entirely possible that adding a generic NPC marker wouldn't do anything, since it can't access the assets telling it what to create. I'm going to attempt to create a map that uses the first person 'free roaming' camera, along with whatever npc models are available in the default Unreal library. Even if the game can load the map, I don't know if there is a way to actually choose a specific map (haven't explored the dev console at all). Maybe a command to choose which maps are available as the starting mission? This is all purely speculation, just wanted to write it down, see if anyone else has some brainstorming ideas.