I started reading through bits of movie scripts for the first earlier this year, and I was actually amazed at just how much description there was. I had always they were mostly dialogue with just a few vague stage directions every now and then.
It varies. Sometimes an elaborate action sequence will be described in painstaking detail; other times it will be more like "she kicks their butts with lightning-like moves."
And just because something is described one way in the script doesn't mean that the art director or the special effects guys or the costume designer or the casting director or the fight choreographer won't decide to go another way on the actual film . . . .
This can lead to surprises when I finally see the movie:
"Hey, nobody told me that character was a woman!"