Film Versus Videogame
If you are developing a videogame, you may not be making a 120-minute film. A videogame is composed of many 3-minute or 5-minute films. These films are played when the character reaches the goal or the reward or whatever. Films are predetermined, but a lot of videogame play is NOT predetermined simply because it is associated with the WASD or whatever control that the player is using.
Videogame movement cannot be rendered in a way that is static. Instead, the developers have a list of things that the computer can display on the screen, in which case the rendering is performed in real time based on where the characters are standing or how they are interacting.