I think the biggest difference is in how the story was presented. Hero Factory's story was always very straightforward, with everything being explained very clearly. Bionicle, on the other hand, had a lot more mystery and intrigue, which was always what drew me in. It looks like Bionicle g2 seems to be recapturing that same aspect of mystery, while providing a simpler story similar to Hero Factory, and so far it's working out great.