In the mobile version of Call of Duty 2, you take the roles of various soldiers fighting through the World War II. There's four years (1942-1945), each one with two soldiers to choose from, each with their own set of missions. Everything but the first missions are locked, and you have to complete them to unlock them later ones, eventually unlocking the next year as soon as you finish every mission in the earlier one....
No lo he jugado aun pero lo espero con ansias y ya lo recomiendo. I haven't play it still but I'm waiting patiently to the date of released and I already recommended.