[Cushman]

That's a good point, and maybe I was too binary in my original statement-- there are a lot of parts of NPC design that are more physics simulation than AI. I'd still say there's a categorical distinction between "respond appropriately to being hit by a linebacker" and "respond appropriately to someone putting a bucket on your head", though. Like you say, we're close to realism on the former; much farther from the latter.