Don't you wish you could have had weapons or abilities in the earlier part of the game? In story mode, the character can gain weapons and abilities and go back to a previous level or save point and utilize those abilities in the earlier part of the story. You simply save before completing a level. After your character gains all the necessary goodies, you then load the previously saved game from the current level. Your character will be transported back in time to your saved level but with all the weapons and abilities you earned from newer levels.
Please see my blog for game development design notes. This is part of the unintended feature discovery.
