>>538801>he even composed the music for it iirc
I think he just cut together already existing stuff but I may be wrong.
And yes, he did it by himself but he was also an extremely talented archviz pro. However in most shots, nothing was animated except for grass and the light pretty much. I think it also was a compilation of scenes he had worked on before, so animating your vraysun and camera and then hitting render isn't that much work compared to animating characters. Still, it was very very impressive.