I think this is an early 80's movie about robots invading a southern US smalltown (farmland etc), I think its set in the 50's. The townspeople are rockabilly style.
Theres a scene where the people are in the local theater watching a film of their own town being invaded.
Thats all I have until I can remember more scenes...
If most of the action took place in a theater, I would say that this was "Invasion Earth: The Aliens Are Here." The aliens play around with a theater full of people in their quest to conquer mankind. I have the LD of this one and keep meaning to review it.
http://www.imdb.com/title/tt0093272/
This doesn't fit your description perfectly, but it immediately jumped to mind.
It Could be Spaced Invaders, although it's 1990. There is a movie theatre scene, if I remember rightly and a killer robot.
Started lookin for this movie again... any other suggestions?