Quote: "One thing about these Mexican horror films I keep meaning to mention is that none of them ever seem to use any optical effects at all. (The worst thing about those Robles films is how he pops offscreen, ala BEWITCHED, to be replaced by a bat, which just looks terrible.) I know that opticals cost a little more, but they sure would have helped these films immensely."

I disagree totally. I saw "El vampiro" in French theaters when it was released as "Les proies du vampire" and the effect was striking, the illusion of Robles changing himself into a bat was totally credible just because it was suggested by editing and not by some opticals. Opticals (as in the old Universal movies, with Carradine then Lugosi changing into a bat in the "House" films and in "A&C Meet Frankenstein" were amusing and generally very well made, but totally unconvincing. One of the effects, obtained by Fernando Mendez's sense of editing - the vampire attacking a little boy - was absolutely terrifying when seen in a theater.