In Halo: Combat Evolved and Halo 2 co-op, when playing a level involving the Master Chief, both players will control two identical copies of the Chief when playing a Halo 2 level involving the Arbiter, both players will control identical Arbiters. Generally however, the benefit of added players more than makes up for the increased difficulty.

Scaling is also found in Halo 4, albeit to a less noticeable degree than was present in Reach. In Halo: Reach this tactic is less feasible, because difficulty 'scales' in co-op the more players, the greater the difficulty. In many of the other Halo games, players will often attempt to beat Legendary in co-op instead of single player, because they consider Legendary too difficult to attempt alone. Additionally, in Halo 2, if two players are playing on Legendary difficulty and either of them die, then both of them have to start at the last checkpoint (similar to the effect that the Iron Skull has on cooperative play). If all players are killed, they will restart at the last saved checkpoint. In the sequels, each level has a designated pair of weapons that respawning characters start with. When a player respawns in Halo: Combat Evolved, they are always equipped with an MA5B assault rifle and a Type-25 plasma pistol. The player who dies has to wait until the player or one of the players who are still alive are not engaged in combat and are at a safe location before they are able to respawn. If one player dies, they can come back to life, or 'respawn'. Co-op gameplay consists two or more people playing through the campaign as a team.

Halo 3 4 player split screen