While the TAS is excellent, there were a number of places that I found questionable.
During the start of mission 4, on the second truck, doesn't R fire faster when crouching?
During the first phase of mission 5, you could get 2 additional slug coptors by sacrificing the previous coptor before a certain point where it appears. Or does that require both players to be not riding a slug?
Also, I can't tell if you had accounted for this, but the second boss of mission 5 will not go below 1 health (yet still give points when hit) when certain parts of its body are out of the screen. During the run, it seems that it may have occured right before it died. Have you checked for this?
Finally, at the 6 brain-mech fight during the clone section in mission 5, the brain-mechs appear with less health and drop weapons (including S) if no players are in the slug when they begin to appear. It is possible to have them appear as such and ride the slug again though.