This movie clocks in at just short of forever, or at least that's what it feels like watching it. It desperately wants to be Argento's Suspiria (and as noted, does a better job remaking Suspiria than Guadagnino ever did), right down to the music, but it doesn't really work very well, for a number of reasons.
The first and foremost is that none of the characters are remotely likeable or sympathetic, making it very hard to become invested in anything they do. In Suspiria, the characters were often simple, but they were immediately comprehensible and often sympathetic. If you didn't like them, their actions at least could make some sense, even if you weren't aware of the subtler motivations that would only come into play near to the end of the movie. With Masks, most every character is suspect and very unlikeable. Plenty of characters only appear to be extremely hard to like, and there are so many unpleasant characters that they all start to run together very quickly.
Additionally, there's no real buildup of suspense at all. Violence occurs with no real reason behind it, and we don't even know the characters well enough to be invested in them. It's just a vignette around violence, and it doesn't add anything to the story. The setting is weird and unpleasant, but it's also stupid and meaningless.
Ultimately, the whole film is pointless. It could have been ten minutes long and accomplished the same thing. In fact, it probably would have been better, because then the threadbare premise wouldn't have been stretched out so thin. There were some decent ideas in there, but none ended up done well. The acting, whether you know German or not, is very questionable and uneven, which doesn't help matters.
The sets and costumes were good. The makeup and style were generally good. There was also a lot of really engaging photography. The music, though derivative of Goblin's classic soundtrack, is well done and just distinctly different enough to work.
But the rest of the production really lets all of the good down. I've said it before, and I'll say it again: just a bunch of unpleasant people does not make for good horror. There was exactly one line, where the main character lost her temper close to the beginning, where someone got exactly what he deserved, but that was it. It would have been much more interesting and enjoyable if it had actually explored the character developing more, which it really didn't do.
All in all, it's not a movie I can recommend. It may be a better take on Suspiria than the pathetic excuse for a remake that deserves to be forgotten, but that doesn't make it really a good movie. They tried, but as with many films these days, especially homages, they would have done better to keep it brief and do a short film instead...and only then develop it if there's enough material to do so.
