An MMO where the living fight the dead. As the living you must reinforce your shelter with objects found amongst the landscape, collect amenities needed for life and stay alive. As the dead you gain your strength from meat. Small creatures will keep you limping along, but to get your run on or move large objects, you'll have to take down bigger meat. A strong physics engine is a must! All objects have weight and mass, which plays into the build function needed for the living to reinforce structures and create traps for the dead. and basically any elements that could be captured from the genre ie: caused by disease, nighttime benefits the movement of dead, military presence, urban vs. rural, weapons of choice for certain levels of dead...etc.