If an extra episode comes out that isn't directly following events of the main game, then newcomers to the brand may give it a go even if the original didn't review particularly well but they hear that new episode has fixed several issues and plays like a better game. (dealspwn.com)
The 2nd DLC Expansion, Friends to the End, is the only one that stays within the canon events of HGH, where Bollo, Sky, and Rottytops venture on a quest to save Shantae during certain events of the main game's storyline. (reviews2go.com)
However, aside from this emotive dynamic the campaign does little to expand on the events of the main game, even though it parallels the original script well. (thesixthaxis.com)