Halo: Combat Evolved Anniversary includes several map packs for use in Halo Reach's multiplayer mode. The Anniversary Map Pack--which includes six multiplayer maps and one Firefight map--will also be available to download separately on November 15, for 1200 Microsoft Points ($15).

Microsoft explains how the Halo Anniversary maps will integrate into both the new Halo release, as well as Halo: Reach.

While very cool, this cross-game content does raise some interesting questions about how it will all work if you own only one game or the other, or both. Thankfully, 343 explains:

• If you own Halo: Anniversary but not Halo: Reach, you will launch the Anniversary maps from the disc menu.

• If you own Halo: Anniversary and Halo: Reach, we recommend installing the maps using the Anniversary Map Pack code that comes with Anniversary. You will then be able to launch the Anniversary maps from both the Anniversary and Reach menus.

• If you purchase the Anniversary Map Pack, you will install the maps like any other piece of DLC. You will then be able to launch the Anniversary maps from the Reach menu.

Halo: Combat Evolved Anniversary blasts off to retail this Tuesday, November 15.