Uses Emoose legacy mod, easy peasy download and drag, drop replace.   Keep the bodies , gibs,  etc. Without breaking the campaign. Note: lots of things last forever others are simply extended due to no way to tweak max a.i allowed. Living or dead.    This has very little (contrary to everyone thinking it would) impact on performance. Try it and see for yourself. ID needs to let is have more control over the values used in the engine for PC players. That's the only reason it h