El Increible Profesor Zovek, but then Zovek went and got himself killed during a break in filming. If that had happened in this day and age, the producers would have simply created some kind of creepy virtual robot or something to finish Zovek's scenes and nobody who didn't pay attention to the news or care whether or not Zovek was dead would be the wiser.
The producers of La Invasion de los Muertos, however, not having access to that kind of technology, had no choice but to insert a bunch of unrelated footage of Blue Demon standing around in what looks like the boiler room beneath a suburban high school and talking on and on at people to fill out the picture. And the shocking thing is that that really doesn't make La Invasion de los Muertos that much worse. By which I mean to say that La Invasion de los Muertos is pretty fucking awesome.
It's understandable why the producers turned to Blue in their hour of need -- seeing as he seemed to be pretty much game for anything that was thrown his way -- but why they then chose to use him as little more than a talking head is somewhat mysterious. From what we see, it's as if Blue has moved beyond using his fists and has resolved to subdue his enemies by simply boring them into unconsciousness.
The apparent desperation to pad out La Invasion de los Muertos' running time makes you wonder just what the consequences would have been for director Rene Cardona Sr. had he not turned in the film at feature length. Could it be that he would have been … killed? Well, that's the explanation I'm going with, anyway, because it's easy enough to believe that, somewhere behind the scenes, there was a gun to someone's head here -- and the price on that someone's head was the imperative that La Invasion de los Muertos be as much of a clusterfuck as was humanly possible. An entertaining clusterfuck, mind you, but a clusterfuck nonetheless.