Hidden in the Terminal Map of Call of Duty: Modern Warfare 3 is a clever reference to Valderas, a map from the last game in the series. Sledgehammer Games' new entry in the Call of Duty series continues the story and action from the previous title while striking off on its own with new game modes and content. Some fans have been asking whether it's important to play Modern Warfare 2 before Modern Warfare 3 and, while this answer depends on a lot of factors, it seems that there are some benefits to having checked out the last game first.