Prerelease:Halo 2

Cut Levels
Two levels are known to have been cut before the game's release.

Covenant Ship
Revealed on Halo 3 Legendary Edition's bonus disc, this level would have taken place between Cairo Station and Outskirts and would have involved Master Chief boarding and destroying the Covenant vessel that attacked Cairo Station before heading to Earth. It was replaced by a cutscene where Master Chief bombs the ship from the outside.

Forerunner Tank
This level would have taken place after Quarantine Zone when The Arbiter and Master Chief fall into the Gravemind's pit. It would have involved escaping from the Gravemind's quick-moving tentacles, but was replaced with cutscenes.