This is standard fare from a director who as long been amongst my favourites.
Even though its very flat in comparison to a lot of his other work but its Argento and this may be biased but I'm gonna be giving it a good review anyway.
It does contain a lot of good ideas. The subtle voyeuristic element. The needles under the eyes. The gory and disturbing deaths. And the Argento cliché flashback.
Downsides include the heavy metal soundtrack, acting and the ending.
All the film is made worth it for the birds in the theatre sequence near the end.
A fairly good film from Argento but he as done better. A lot better!