I remember thinking a long time ago, when the pictures of the demons were first released, that I was a little worried that the movie would get bogged down with baddies. For context, I believe that's what was mostly wrong with Elektra. There were too many baddies... without the necessary development, or something.
Anyhoo, I'm not so much concerned with that in the movie anymore. It seems the baddies wont really need that much development because of the easy classification of them all being demons.
Anyhoo, as for the fights, I expect there to be mainly one night of fighting or maybe a couple. I expect him to take care of the henchmen fairly quickley, the only trouble really coming with the fact that they'll likely be together for most of the time. Of course, I'm only guessing on this. He may take them out one by one, which also appears to be the case according to the trailers. It's hard to tell really.
What I do know is that we'll see GR use a lot of powers to take these guys down, which I really like of course.