Have it set somewhere that the flood have taken over. Or New Mombasa after the flood arive. You play as an ODST or a Marine trying to get out alive. Dead bodies, blood, maybe a few jump scares but keep it more demented.
You go through the city fighting the covenant then when the flood crash in you recieved orders to move out. When you get to the pickup zone where the pelicans were suppose to be all you see is a downed pelican with blood symbolizing the bodies from the crash were dragged away. Your goal now is to find any way to escape. You retrace your steps to where you entered the city. The bodies of the covenant and your fallen brothers are gone with blood everywhere… the rest is up to the Devs.
What do you think?