The uploader of the video is Gregor Punchatz who worked at studio Janimation way back in 2008. His team worked a vertical slice for this cancelled prequel of the Duke Nukem franchise that Gearbox had once worked on at that time.
For those uninitiated, a vertical slice is a portion of a game which acts as a proof of concept for stakeholders before they agree to fund the rest. It would the same as a prototype and expected to look of final quality and play like the final game. It would usually be CG visuals and nothing of core gameplay, but it is expected to look that way later on.
The video shows that it was going to be a third-person shooter, dual-gun gameplay, and had co-op mechanics. It was ambitious for a prequel at that time, but no word on the reason for its cancellation.
According to Punchatz, he wanted to share this video because it is a “piece I am damn proud of”. He released it after 13 years since its creation. He also said that his whole team who worked on it deserved to see this released into the wild.
Punchatz hopes that Duke Nukem Begins could somehow be resurrected with this release. He wanted everyone to see how incredible it would have been. Who knows, it would pique the interest of other studios want to take a shot on this.