Nep, he probably took some screenshots + edits. It's quite laborious, especially with the different angles you have to deal with, but it works.
As mentioned, you can see the difference in the quality of some elements. For example, behind the sunflower is quite sharp on the ramp, although the sprite is using some blur.
With some more editing the stage will be perfect.
Jojo: Ridiculous Expository Adventures
It's just like a podcast.