The game plays exactly the same as the Halo PC that you know the menus are navigated the same way, and the gameplay is given the same controls. The code has been changed, to better support online play. The rules are displayed when you join a game, and are available all throughout the game. Though the main addition of Custom Edition is the ability to play custom maps, a few subtle things are changed as well.
You may use Custom Edition and never touch a single-player level, but I'll talk about it in this guide for people that want to know how to install and play one. Some are complete with cutscenes, Pelicans, the Covenant, the Flood, and the works. You can load them and then play through a Campaign-like mode. In addition, some maps are made for Custom Edition that are single player. Those are custom maps, and if you install the map too, you can play the custom map with them.
You'll also notice, that when you load the list of servers, there are a lot of map names listed that you probably don't recognize. On the main menu, you'll notice that there is no option for selecting Campaign only Multiplayer. Most of the maps made for Custom Edition are multiplayer. Now players can make their own maps, or own weapons, or own vehicles. Its main function is to allow the use of custom maps.
What is Halo: Custom Edition?Halo: Custom Edition is a version of regular Halo: Combat Evolved for the PC.