Custom Game

A Custom Game is a customizable gametype in Halo. Which weapons and vehicles appear on the map, the time limit and kill limit for each match, and health, shields, and visibility can be customized.you can also set the weapon capacity limits and can set what weapons will appear on the map, also as a starting weapon.You can also choose a game match. And you can choose grenades to start off with.

It is the same thing as "Splitscreen" from Halo 2 or "Custom Games" in Halo 3.