The reviews for the first-person shooter Call of Duty 4: Modern Warfare were all very high. IGN gave the game a 9.4, GameSpot gave the game a 9. One of the negative comments concerning the game was the shortness of the campaign mode.Call of Duty 4: Modern Warfare Review There is also no co-op during the campaign mode.Call of Duty 4: Modern Warfare" ReviewNew additions and improvements to the game include more enemies, addition of enemy dogs, and perks during online multiplayer mode.Call of Duty 4: Modern Warfare" Review