From the article they list a bunch of arbitrary constraints...

> If this sounds unreasonable to you, that is because it is.

Those listed, are tame. I don't understand this kind of faux modesty.

> My goal was to build a complete, shippable first-person shooter using techniques that were common in the early 90s

Goes on to explain how they used 3D blender...which wasn't available until 1998.

A vanity cat project being tailored and submitted for nostalgia clickbait. I don't think there's anything useful to take away from this other than some color shade selection ideas.