I did find one that WAS actually pretty bad that involved blood and gore, the game being haunted and get this... the end of the story is an "action movie" with the main character going around killing monsters that "were coming out of the game". I'm not kidding.
Creepypastas I think can be good, or bad... MARIO is probably the best one IMO, being about a SMW hack... And it actually is a true story. It's not "haunted" or bloody... It's just a strange hack, I reccomend you look it up. ((And the txt file that comes with it apparently can be converted into a freaky image))
Those stories were poor, but as the video commentator says, they do have promise. The Sega Legacy one could have worked, had the game had:
A: A reason for people to go crazy. Sonic turning into Robotnik and being killed by another Sonic is not particularly creepy. It's an amusing fan theory/fan fic premise that would at best annoy a couple of people on the internet. Unless the people in the story are all die hard classic Sonic fans who hate modern Sega and kill themselves over the 'betrayal' of their childhood, that twist makes no sense.
B: Some sort of real reason to believe, care or think about this 'Sega Legacy' thing.
That and less over the top violence and death for the sake of it.
The Wario Land one... well, the idea of the Hidden Figure being evil is pretty cool, since Rudy the Clown is exactly the kind of character who would do this sort of messed up stuff. The idea of the temple being a full level makes me want to see that in an actual Wario Land 3 remake, hack or fan game.
But then... they just had to go all over the top with the supernatural stuff. Fine, supernatural stuff can be creepy. But characters escaping from works of fiction and having to be killed in the real world?
What is this, a B movie or kids cartoon?
http://tvtropes.org/pmwiki/pmwiki.php/Main/RefugeeFromTVLand
Is this real?
Cause that's hilariously bad.