If I were to make a zombie game I would have an unavoidable level where you will pass a school. An infinite amount of zombie children will rush out of the doors and it will take you about 30 minutes for you figure out how to close the doors and trap the zombie children within. Then an NPC will pop out of nowhere and start lighting the school on fire.
No doubt there would be people on youtube posting tips on how to shut the doors without killing any children. I'll fix that because I will make it so that you aren't allowed to leave the area until all remaining zombie children are dead.
I don't care how much controversy that would bring and I don't care how much people will stop buying my game. It's all about the artist's creativity, I will not allow some soccer mom to censor my creativity. Besides if they feel so strongly about it then why are their children playing M rated games?