i love b-movies. i love the sentiment behind them: that a group of people battle through production with next-to-no money, drawing on very limited resources to source props, sets, scripts and actors - putting all their soul into making the best possible film they can. tremors was a b-movie. clerks was. piranha / so i married an axe murderer / evil dead / evil dead 2; they all were.
they all were because their creation was genuinely to make a genuinely great film. the cult followings have come from an empathy with the audience, the striving through hardship and the ingenuity with which rubbish resources have been manipulated into something passable and loveable.
b-movies are greater than the sum of their parts.
mega-shark vs giant octopus is not a b-movie.
mega-shark vs giant octopus is far too knowing, and too self-aware. it is too obvious that the film-makers had set out on purpose to make a "B-MOVIE!" with all the traditional conventions of the genre. essentially they've set out to make a parody, and when you do that you need two things:
1. you need to know and love the thing you're parodying.
2. you need skills to do it well.
mega-shark vs giant octopus was clearly made by people trying to "cash-in" on the b-movie cult, and you can't empathise with someone you're trying to grab money from.
and it was made by people with no skills and no sense of humour. there was no innovation, no struggle, no ambition. it didn't grab you by the heart or surprise you, or give you any reason to like it. it deserves no more praise than any wayans brothers movie.
therefore it is not cult-worthy. it is not "so bad, it's brilliant." it is not witty. it is not good.
watch slither instead.