9. Left for Dead vs. Dead Rising's Zombie Genocide
Nothing wrong with a little friendly competition between two video game developers with comparable concepts. Supposedly such a rivalry does exist between Left 4 Dead and Dead Rising as the developers play their own game of outdoing the other. In Dead Rising an achievement entitled "Zombie Genocider" can be unlocked once the player had made approximately 53,594 zombies. That's a pretty freaking huge number of the undead for anyone to kill. Not to be left behind in the game (yes, it's intended) Left 4 Dead then came out with an achievement called "Zombie Genocide" that required the player of off exactly 53,595 zombies, effectively allowing Left 4 Dead to say that it "one-upped" Dead Rising.