One of the unique aspects of Oneshot is the interaction between Niko and the player, which quickly forms a bond and results in a memorable experience.
In movies you are an observer, and apart of some fringe cases, you never have any meaningful interactions - you usually just enjoy the ride, hands-off.
Despite all of that you can probably still make a good movie in Oneshot universe or with Niko&co., and if Niko would be the focus, then I would expect it to be set in a "dream world", where there were no player interactions (IIRC).
Dr. Zbigniew Religa, operated on Tadeusz Zitkevits, no idea who the assistant was.