Star Vin Diesel and writer-director David Twohy clearly love Riddick. You don't dig up an old franchise character that no one remembers that much without some sort of emotional attachment or care. What's less clear is if the creative duo knows why anyone else likes the character. Diesel and Twohy are driving the Riddick bandwagon, and they don't seem to care if anyone else bothers to hop on. It'd seem nobler if the movie wasn't such a slog.