Halo 3: ODST

Nathan Fillion, Adam Baldwin, Alan Tudyk appeared together in Firefly (2002).

Regret's Assault Carrier acts different than it did in Halo 2. In Halo 2, it flies to the outer city and then jumps while in this game, it is not moving at all and then just jumps.

When completing the game on any difficulty there is an epilogue after the credits. The epilogue that plays after completing the game on any difficulty besides Legendary starts off one month later with Dare and Sergent Johnson talking about the next mission. Sergent Johnson then informs the Engineer that he intends to ask it everything it knows about the Covenant and whatever it is they're looking for. If the game is completed at the Legendary difficulty level, a scene after shows the Prophet of Truth overseeing some Engineers uncovering a Forerunner artifact buried beneath the Superintendent's data core.

Edited into Halo: The Master Chief Collection (2014)