Valve Anti-Cheat Engine would totally save money, they are reliable, strict, and brutal against cheaters, and hackers
"All VAC bans are permanent - Valve has a zero-tolerance policy for cheating and will not lift VAC bans under any circumstances."
Sell this game on Steam for price range of $20-30
Improve windows 7 support and Windows 8 support, and Get Rid of Dedicated Servers.
The graphics should be DirectX 11 HD quality by expanding anti-analysing to 8x sampling, which would make the game inviting to play and enjoy.
The Physics for the game needs to feel realistic in terms of how the actions flow.
The Coop offline and online should be in for classic play of the game. How ever it should be allowed to have up to 4 players to enjoy the excitement and experience of the game.
The Matchmaking that was on Xbox Live, With Classic Game Modes, Plus Ranks 1-50.
Clan Forming
Completely scrap the map editor, its a huge was of space on peoples hard drives, resources, and is completely unstable and never has been patched
Completely improve Xbox 360 controller movements, and Allow a driver for the original Xbox Control to work with Halo 2.
Allow Cross Platform Compatibility with Xbox Live Players on the New Xbox.
Allow Scoreboards and leader boards online.
Improve the weapon sounds, and the damage they do.