Plan 9 from Outer Space

I've finally sat down and watched this, one of the most known bad films ever made, by one of the worst script writers ever.

And, wow, what can I say? Why do all the actors deliver their lines without any hint of feelings? How come nobody seem noticeably shaken up by small, flying hats tumbling across the sky?
Why do the really advanced aliens have no way of communicating with the humans, and when the humans finally build a way to understand the aliens, the aliens don't want to talk any longer, and then they happen to have a translator in their spaceship?
Why do Eros and Tanna have to kill the humans so that they won't tell the world, when the aliens had been trying to get the humans to acknowledge their existence?
Disregarding the stupid physics, why would humans make a bomb that would ruin the earth?
Why don't the aliens just animate all the dead on the graveyard(s?) instead of just one and one?
What happened to the scars from the "puma-like" attacks Vampira were supposed to inflict on her victims (and why are her arms/hands bigger than her waist?)? What happened to the grave diggers? Why are the animated dead vampires? Why do the people in the film have such horrid night vision that they can only see a few inches in front of them?
Why doesn't time pass for people not in shot (police men talking about looking for the inspector, we see the inspector attacked, then the police decide to go look for him)?
Not mentioning the changes in night and day shots, why is the Trent couples' car in front of a black wall? Why did the dead turn into skeletons when the space ship went away? "Dracula" only turned into a skeleton after being shot with a ray.
Why do I even bother to ask questions about this film?

Watching it you just end up being amazed that nobody spoke up about the horribleness of the film. I have a hard time believing so many actors can play that badly. The film is so horrible that it ends up seeming like a parody of bad sci-fi films, and several of the lines would have worked if they were uttered sarcastically (or with a pretense of feelings).
My favourite character has to be "Patrolman Harry" who's been cast as the "dumb cop" and plays so unconvincingly that he seems to be making fun of his lieutenant.
If nothing else the film serves as a "how to not write or direct a film" and seem to have been used as a blueprint for several newer films, most prominently the norwegian/french "Lies. Inc".