Main Idea
Takes place after transporting out of Nova Prospect. You end up in another city in a building everyone will recognize and go "Really Pain, this is where you wanted this to take place? You went in this direction?" and I'll just smugly smile behind my keyboard.
Player teleports in, meets up with an NPC, is given back story into where he is and what's happened to some of the rest of the world after the invasion. Work your way down to the bottom of the building, get into some shootouts and fight your way down to underground tunnels. Take the tunnels to a laboratory and get transported back to the lab.
Some creative map design and placement will allow for an incredibly large vista / 3D skybox as well as the underground tunnels and bottom floor of the map to be on the the same map.
I'm really not much of a puzzle person, so if any it will be a battery or power plug puzzle.
Will need a couple custom textures, a few custom models, and a lot of voice overs I can do myself. Probably won't even bother face posing due to time restrictions.