Differences

From Halo - Wiki on Neoseeker

This section will list the currently known differences between the PC port of Halo 2 and the Xbox one. This will be updated on a regular basis as new information regarding the PC port is released.

Multiplayer

- Bungie has confirmed that a Multiplayer Map Editor will be available in this game, although the current mechanics and format of the editor are currently unknown.

- It Is rumored that the WIndows Vista is going to have a similar system to Xbox LIVE!, and Halo 2 will likely be compatable with that if it is implemented.

OS Requirement

- Bungie has stated that Halo 2 [PC] will only work on Windows Vista, the new Windows OS (to replace XP) due out later this year.