It's been a dispiriting day.
My goal has been to start with basic movement and one-on-one combat and expand outward from there. By the end of Sunday I had a decent-feeling movement and sword-swinging action. I didn't have any collision between swords and people yet, though. The thought of doing that myself was somewhat daunting so I decided to bite the bullet and switch over to a 2D physics engine. I've used Chipmunk in the past so I went with that.
What followed was the usual wrestling with Git to get the project set up. Eventually I did, and converted things over. But I haven't been able to recreate the feel of what I had. In particular, the AI movement is really loose now.
I think it may be quicker ultimately to go back to doing things myself, implementing sword collision myself. I'm weighing it. I need to get on to group movement patterns and challenge gameplay.