In that case MLA is really not for you. The scenes of war they portray is rather realistic, and its a war where mankind is in decline against the monsters. While there are few innocents killed, its because there are few innocents left. I suggest you stop after unlimited, and not play Alternative. This is a game of epic levels of despair, sacrifice, and finally, hope.
If you really want to see a sampling of the Alternative world, you can watch the anime Muv Luv Alternative: Total Eclipse, which is a spin off side story of the main series. The first two episodes has a small sample of the war trauma that is portrayed in the main series. If you can take that, then by all means, read the VN. It is really epic.