Also, I think there should be anti-alien combatants in some terror sites. Not policemen though. To keep things simple and belivable, I think only military-style soldiers should be around. Having police in terror sites is silly. Not every country in the world has policemen, at least not in the 'blue-uniform-with-a-pistol' people would think of as a policeman.
Since the storyline describes several mindnumbingly horribly assaults on civilian population, it can be assumed that every nation with a city worth terrorizing is under martial law. Soldiers EVERYWHERE. Thus, a terror site or other urban mission will have drab, crappy conscripts responding to the invasion rather then civilian police. To make things simple. add on some armed units (That do not attack without the playe'rs base, alien confinement and "
I also really hate the idea that civilians would have pistols or other weapons and that they would fight back. Guess what. Weapon ownership in most nations is strictly illegal. The USA is the only nation in the world that offers such liberal gun-ownership freedoms and by 2057, I'm certain that movement will be gone. It gets more and more illegal as the years go by. By the year 2057, its safe to say no civilian has access to anything more lethal then a cowering stance in the corner.