Even then, by my understanding, that was mostly for the port and bug fixes. CA was very reluctant to give any control and did all art, musical, feature, and overall directional development himself.
I'd argue it was a recipe for burnout and generally a bad idea but this is what I remember from when I obsessively read his update blogs back then
If he has CA's blessing to make it with the same art, then I look forward to it. If he just copied CA's art without asking, then I hope whatever measures CA takes work out in his favor.
It doesn't look like the exact same assets, but it clearly has the same color palette and design. Honestly it kinda feels like a slap in the face, but maybe the two of them came to some kind of agreement? ¯\_(ツ)_/¯
Are we looking at the same screenshot? I see many assets that look the exact same as SDV. Bushes, the sand and grass floor tiles, the fence maybe?
Edit: Did some digging and apparently this is some engine the dev was working on while doing stuff for SDV and the ConcernedApe is cool with it. That explains the copied base assets.