Custom game is partially the Funnest bit of the game, in the custom game menu, you can set up your game; what map you want to play in (only Base, Convoy, Convoy [Night] , Mansion, Mansion [Dusk] , Mansion [Lab] , Market, Market [Day] , Factory, and Isolation are available) ,the amount of points needed to win, the allowed class type (All classes is an option) the different types of game modes (Deathmatch, One Man Army, Gun Game, Team Deathmatch, Capture the flag, Domination, and Team Gun Game) ,toggle whether Skills, Killstreaks, and Armor are enabled or disabled, what modifier will be used (No Modifier is possible) (You will have to achieve hidden achievements to unlock modifiers) (Modifiers are pretty much pointless except for Isolation's Low-Gravity cannot function without Sky9, and Fiesta mod is crazy with weapons and winning chances, all the others just give you infinite ammo and some downside) , what the difficulty will be, and select the other players.