#6 Halo 4
Like all previous titles in the Halo series, Halo 4 offers a fully cooperative experience with vehicles designed for more than a single occupant, and maps and challenges that more or less require teamwork to overcome.
While the game’s campaign is certainly playable alone, it’s a lot more fun when you have a friend to watch your back.
In addition to the game’s single player campaign, Halo 4 comes with a full fledged co-op mode called Spartan Ops. Spanning over 10 full-length episodes and 50 missions, up to four players can team up to defeat renegade Covenant forces and Prometheans alike.