Call of Duty: United Offensive

The first Call of Duty from 2003 raised the bar for World War II shooters with its emphasis on cinematic battle staging, switching between American, British, and Soviet soldiers, and combat dynamics where the player isn't the sole hero of the battlefield but part of a larger squad, whose fellow soldiers shout orders and react to events around them. The game quickly won people over with both its single-player campaign and its multiplayer, becoming one of the founding titles of the entire series, which later grew into one of the most successful game franchises of all time.

Call of Duty: United Offensive from 2004 is a standalone expansion pack for PC that, unlike the base game, wasn't developed by Infinity Ward alone but jointly by studios Gray Matter Interactive and Pi Studios under publisher Activision's oversight. The expansion added a new campaign expanding the story with the Battle of the Bulge, the Soviet defense of Stalingrad, and new missions playing as American paratroopers, filling in the gaps between the fronts that the original game had left to itself. Another major addition was drivable vehicles — tanks and other armored vehicles could be piloted directly for the first time in the series, changing the pace and tactics of individual battles and adding a vehicle-combat element to what had been an infantry shooter. Multiplayer also raised the maximum number of players per match and added new modes and maps built specifically around tank battles, which later became the foundation for multiplayer in later entries of the series. Because it was a standalone expansion pack rather than a full sequel, players could buy just the new content without needing to buy the base game again, which was still a fairly unusual approach for war shooters at the time.

Why play: United Offensive will appeal to players who loved the first Call of Duty and want a longer, content-richer continuation with vehicles and new fronts, without having to wait for a whole new entry in the series.