There is no story to the Campaign in World Domination. It is played out like the game mode, Galactic Conquest, in Star Wars: Battlefront II. Players will face AIs in a struggle to dominate the world. Each player/AI will choose their own faction, or country, and may form alliances with others during the game. The player can choose the number of AIs to participate, from 1 to 5 (making the maximum number of factions 6, including the player).
The actual gameplay is turn-based. One faction will make their move into enemy or friendly territory. If friendly, they can choose to command any units however they want, but other than that, it's the next faction's turn. If enemy territory, a random map in the specified area will be chosen, along with a random gametype, and the two factions will battle it out regular-CoD style. If one of the battling factions has an ally or two, the allies can choose whether or not to donate weapons, soldiers, vehicles, supporting abilities, etc. Whichever faction wins the battle will gain the disputed territory and the losing faction's soldiers will head over to their nearest friendly territory.
When the player has one or more friends on the same console (Imagination only), the other players can choose whether or not if they want to join the host player's faction or not.
There are multiple difficulty levels in the game, like in the canon CoD series. These difficulty levels are:
- Main article: Call of Duty: World Domination/Multiplayer
Co-op Campaign is the multiplayer version of Campaign and is extremely similar except players can play with any other players around the world and there are more gametypes. Any rank achieved in regular Multiplayer will carry over into Co-op Campaign.
- Dominator - Finish your first Campaign as the winning faction on any difficulty.
- Supreme Dominator - Finish Campaign on any difficulty five times.
- Conquerer of all the Known World - Finish Campaign on any difficulty ten times.
- Domination Master - Finish Campaign on Veteran.
- Domination Veteran - Finish Campaign on Veteran twice.
- Go Outside...Seriously. - Finish Campaign on Veteran five times.
- Maybe Next Time - Finish a Campaign as a losing faction.
- First Blood - Win your first battle in Campaign.
- With Friends Like These... - Make your first ally in Campaign.
- Unconquerable - Never lose a battle or any territory.
- Just Like Old Times - Have Russia defeat Germany in any map in Campaign.
- Staging Revolution - Have the U.S. and Great Britain ally, but then break up.
- Upcoming Commander - Win your first Campaign.
- Online Victor - Win 1 online battles.
- Successful Tactician - Win 5 online battles.
- Elite Tactician - Win 10 online battles.
- Master Strategist - Win a Campaign without any battle or territorial losses.
- Making Friends - Become allies with another player.
- Unsuccessful Partnership - Lose ties with another player.
- Rookie Nation - Join an alliance (multiple nations together already).
- Youth in Revolt - Stray from an alliance.