Back in March 2008, contents from Sonic Unleashed were leaked to the public, this included an early trailer and some images from an early, more unfinished version of the game's opening featuring presumably earlier, unfinished lighting, animation and models. What's interesting enough is that for some reason, the frame of Sonic screaming from that early opening caught more wind compared to the frame from the final FMV, and some people even misremember it as the actual frame from the opening. The misconception about the frame was 'solved' in 2022, bringing the common to the information that it came from the leak, but the complete animation is still missing.
All that the public has right now from the FMV are the few frames that were leaked, and I'm not sure if SEGA has more, or the full animation given their infamy for losing files and source code. You can find all the frames from the early FMV on the TCRF page.