It was chilling to see a game I know twisted into something else. Recently, I found a similar story about a Majora's Mask Cartridge. That story is here. These stories had a big impact on me. I think it would be awesome to see DLC that plays off of this idea of a perversion of the original text.
Rockstar is doing something similar with Undead Nightmare. They're taking the players' expectation of the game world and twisting it to create a whole new feel that's exciting to play through. In a game with a strong sense of narrative, I think this can be very effective.