To my knowledge there is no other movie before (and for many years after, until Friday the 13nth) totalling 13 murders. I am not giving anything away, the number is on the box so you will notice it! Several early 80s slasher movies borrowed this kind of narrative, others, Friday the 13nth, chunked out a whole scene.
What sets this one apart from the others, is that there is no "maniac" running loose. This makes a huge difference in characterisation. And of course much more compelling. The plot and the motive are more in line with some classic narratives and early gialli, rather than the obsessive themes of Argento, but the very graphic gore makes the difference.
Arrow's release is great value for it's price. You get an English HD version and the Italian non-HD version. There is a difference of opinion regarding the color of the English version, not being as saturated as to instantly strike as a Bava movie, but since you also get the Italian version which allegedly is more authentic, 4 reversible covers, two of which are spectacular (personally i do not like the one shown, but that's my opinion) i am guessing it will be the European release to get for quite a while. An Italian company has also released this in the past, but they don't do Blu-ray yet.
A long special feature regarding the writer was very interesting, not so much for his work (LOL!), but as to the insider info on 3 prominent directors (Bava, Argento, Fulci). Also, subtitles are included for both movies and the features, which was a true fan service for those who are non-native English speakers. Thank you!