I'm not sure why they don't just hire voice actors and ask them to naturally respond to the situation while watching the video, with a set of target phrases. "

I'm not sure why they don't just hire voice actors and ask them to naturally respond to the situation while watching the video, with a set of target phrases. "Say something to the effect of this, when this thing happens on screen, but phrase it however you like." Visually stunning, but no matter how realistic it is, you're killing the chance of enjoying it because you go "Nobody would say that", and it also doesn't sound natural. This is why I enjoyed the Fallout games so much. Even the earlier ones like 3 and New Vegas that weren't realistic looking had fantastic, believable dialogue.