From Halopedia, the Halo wiki
The Reclaimer vacation is a glitch in the Halo 4 campaign level Reclaimer which allows the player to break the boundries of the playable area and explore the level at will. It requires the Tilt skull and the jetpack Armor Ability and can be performed on any difficulty.
- Start the level at Rally Point Bravo. Proceed with the level as usual.
- Upon arriving at the entrance to the underground complex, enter the tunnel while meleeing. This is to prevent the checkpoint from loading.
- Once you enter the first room, turn to your left and, while still meleeing, jetpack up to the ledge.
- Once you are situated on the ledge, cease meleeing. This will cause a checkpoint to load.
- After this happens, use an Explosive jumping trick into the air. While you are in the air, jetpack up to the small ledge in the right corner.
- There is an opening in the wall behind you. Jetpack up through this.
- You are now out of the map and may explore at will.
- A large room, adjacent to but unacessable from the playable area, can be seen. Sections of its walls flash yellow. It is unkown what purpose, if any, this room serves.
- Walking atop certain rooms will trigger checkpoints and dialogue.