A well designed color scheme helps player play the game. With a clean color scheme, everything in game can be separate and player won’t mistake one thing for another and miss some important visual information. It can also help player with identify the enemies or pick up, and orientate themselves in the game world.
Example: Team Fortress 2 In Team Fortress 2, players are separated by blue and red. And most time the environment use yellow, white dark green and avoid using the similar color with players, which makes players stand out from environment and easy to identify. Also, designers slightly add slight blue element in blue team controlled area, and slight red element in red team controlled area, so players can always tell where they are even the map is completely symmetrical