I realise this must have been said numerous times already, but this game is not at all a sequel to the 2009 Ghostbuster's video game. So why does Sanctum of Slime advertises itself as the sequel?
While Ghostbusters: The Video Game featured all the actors, an original story, and was a true Ghostbusters game, this game is just an extremely poor game with the Ghostbusters license slapped onto it, like the Ghosbusters videogames before the 2009 effort. Nobody who had anything to do with the 2009 videogame, has worked on Sanctum of Slime. I'm pretty sure people like Dan Aykroyd and Bill Murray have no idea of this game's existence.
Ghostbusters: The Video Game is probably the first entertainment product to be released since Ghosbusters 2. This however, has nothing to do with that. And I'm also not counting the cartoons, who also had none of the original actors and writers. The only thing those have in common with the movies are the soundtrack.