Ross Hendry’s review published on Letterboxd:
Having never heard of Walpurgis Night, the English title would have meant I didn't find the contents of the film quite so surprising. I've only seen one other Naschy werewolf movie, I think, and that was years ago on a grainy VHS rip. This remaster looks much better, but the film itself is still as oddly amateurish.
It doesn't really make all that much sense, and you have a werewolf, vampires, and possibly a zombie to contend with at various times. There's also the same slow motion effect used in the Blind Dead series to stretch the running time a bit, I mean, to make it seem more menacing.