I just realized I can't find the original code on this guy's website but I have the extracted Amiga disk image from a public domain disk circulated at the time... so, here's the annotated 1987 K&R C code on pastebin for comparison:

RT1.C http://pastebin.com/67KWYV3p

RT2.C http://pastebin.com/pc3Uq2Xd

RT3.C http://pastebin.com/v4Qx0gTD

For what it was aiming to do, I think it makes a lot of sense, albeit it might be a little bit too factored for the data(e.g. passing in the whole world to functions called only once).

You can kind of tell that this is more "proof of concept" than "artistic triumph" because the scene itself is relatively bland stuff, with its most impressive aspect today being that the juggler actually animates somewhat like a person. Everything else is just a straightforward demonstration of the Amiga's compute resources and display capability. Since the output was always going to be a single prerendered animation, deep optimization probably wouldn't be worth it.

i mean stuff like the wonky reflection code and checkerboard logic... its a bit 'special', even for a proof of concept.

its unexpected given the apparent intuition for rendering/geometry/maths from the simple, yet clever animation used.