To be fair, this review is based on a Spanish language version of this Mexican horror-comedy film, without dubbing or English subtitles -- and I don't understand Spanish. But in a way, it's a credit to the movie that I still consider it an "okay" time-killer for a monster movie, despite not being able to comprehend a word of dialogue.
The main interest in viewing this is for a chance to see Lon Chaney in the parts of a werewolf and a mummy for one last time in a feature film. He doesn't have any lines anyway, so you're not missing anything there. Though this is supposed to be a comedy (and may very well be if I could register the jokes), it also plays pretty well as a straight-ahead horror feature. There's a comical character played by Mexican comic Tin Tan, who seems to hang out in a museum full of wax figures. Then later on, a really bloated mummy (Chaney) is featured on display but gets stolen by a team of scientists. Back at their laboratory they un-bandage the carcass and he turns out to be a regular guy who resembles an over-fed version of Larry Talbot from the old Universal Wolf Man pictures ... even wearing his same dark shirt and pants. When the full moon rises, Chaney is at his old stuff again, transforming into a werewolf and causing mayhem. Considering this had to be made on a low budget, it's not too badly shot. The Chaney werewolf scenes are the main reason to watch this, and Lon looks good and fierce during his initial transformation, even adding a pretty terrifying growl. Luckily there is a lot of wolf man time on display, though once he's up and stalking around it is debatable whether it's all a stunt man or sometimes a mix, with Chaney alternating in the makeup.
There's more history to this movie. Later on, hack director Jerry Warren tried his hand at Americanizing this by cutting out all the comedy, slicing the running time by about 20 minutes, dubbing it into English, and adding different scenes from some other foreign mummy movie, which made no sense and dragged on. That version can be seen under the title THE FACE OF THE SCREAMING WEREWOLF, but most fans (including myself) would recommend LA CASA DEL TERROR as the more desirable of the two. It would be nice though if an English dub or subtitled version would be made available one day. Might even boost the rating by a half star. ** out of ****