The original (one of the greatest movies of all time) story was complete after the first movie ended.
Every movie after that has been visually enjoyable but the story just sucked.
Here are the stupid parts, to me anyway:
Spoiler
I think so anyway, it was never actually explained in the 20 seconds used to tell the backstory. I think we were supposed to assume?
Actually I can't even continue with the story part because it's so disappointing.
The rest of the cast does a good job although I found no one to be really likable and wouldn't have cared if any had lived or died.