The Question of Separation -Joe Chan

Today's post is less of an argument and more of a question to the readers, how exactly do we distinguish the two genres? One of our group's biggest question revolves around whether the two genres are even seperate or do video games really derive from movies?
One of the biggest barriers between videogames and movies had largely been the need for real acting. Although some games make use of voice acting, there is no way in which any acting in which the body and the face are taken into the account. This raises the question of what is considered real acting and how do animated films separate themselves from videogames? In my previous post I discussed narrative and interactivity being the concepts that separate the two genres but are they really the only two factors that decide the difference between video games? Besides, narrative is a questionable argument because video games have their own form of narrative. Interactivity does not necessarily affect the narrative, in games such as Mirrors Edge you may interact with the surrounding world but the narrative and even the path in which you run are all predetermined to an extent. If videogames are to be marked differently from movies due to their ability to immerse the viewer, how does this bode for old scratch and sniff movies or current 3D and 4D (interactive in the form of chairs moving, smells emitting, objects being release, etc) movies?
Even with these factors ignored, the argument for acting is now further nullified with the use of performance capture which has the ability to capture the actor’s face, body movements and everything that is the actor and place it into a game or animated film. In games such as L.A Noire, the face is particularly focused upon because the player must analyze the actor’s faces in interrogations in order to solve the cases. Here is an example of how performance capture is incorporated: http://www.youtube.com/watch?v=d8jQDykEr2Y.
I am currently at a loss as to how the two genres differ and I pose the question to you readers. How do we define the difference between video games and film?