From Halopedia, the Halo wiki
The achievement can be unlocked by playing Exodus in any difficulty, but it is recommended play it on Easy.
- One method to unlock the achievement is playing the level in Co-op: in the section where the players must use the jetpacks, one of the players must cross the jetpack section and the other will stay behind; the second player will appear near the first one if they separate too far. Its recommended that the player who use the jetpack must have unlocked the achievement already.
- Another way is using a second controller.
- A third way to unlock the achievement is carefully walk through the railways in the jetpack section, and near the end of it, use a grenade and a gravity hammer to jump into higher ground.
- A fourth way to unlock it is play the level normally and use armor abilities whatever you want, especially in the jetpack area; when the player reach a checkpoint, save the game, and then close MCC. After doing this, return to the game and finish the level; the game will register you didn't used armor abilities and the achievement will be unlocked.
The name of the achievement refers to previous titles in the series not having any kind of sprint or armor abilities, meaning the achievement is unlocked by completing the level "the classic way".