Thunderbolt Games: "Activision have such fun releasing sequels each year that they've even coined their own term for it, annualisation. Shocking, I know; but because of this, development on Call of Duty has been split between both Infinity Ward and Treyarch, allowing for a two year development time for each team. Infinity Ward had massive success with Call of Duty 4: Modern Warfare last year, so now it's time for Treyarch to step up and deliver after the disappointing Call of Duty 3 two years ago."
