The Guardian Sentinel was originally set to appear in Halo 3 as a fighting enemy in a Campaign level that later became the multiplayer map Guardian. The player would have been able to rip out the Guardian's eye beam and use it as a weapon in the campaign level.
- The Forerunner hologram in the Halo 3 multiplayer map Epitaph bears a strong resemblance to a Guardian.
While developing the Halo games, Bungie, 343 Industries and Ensemble Studios have had to cut some content, such as vehicles, gameplay, and story elements, from the final products. Much of this content has been confirmed by videos and commentary in special edition DVDs, interviews with developers, and released concept art.