you'd expect C to do a lot better in the line-count department
You would but it's worth keeping in mind this implementation is constrained by closely following the structure and logic of the original. It's like writing C but being told exactly what state you have to maintain (and where), down to the bit, in advance. It really is a 'hardware simulator' where the spec and input handed to you is the sequence of memory states (and a few other bits) of the original machine.