Okay, so I cut out all of the junk DNA. This way, we can see what the DNA is actually doing:
start
*.eyef 0 !=
*.refxpos *.refypos angle .setaim store
*.refxpos *.refypos dist 700 div *.maxvel mult *.refvelup add 9 floor *.maxvel mult .up store
*.veldx .sx store
-6 .shoot store
stop
So, by comparing the two versions, we can see that the .aimshoot line was rendered nonfunctional, as well as the .shootval line. Those are the major changes. A third change was *.maxvel ceil changing to *.maxvel mult in one location.
I can't tell if the *.eyef line was in the original or not, but I assume it was.