I'm not going to bother with a plot synopsis since you know what the movie is about and there's almost no plot, anyway. I've seen several reviewers call ISOYG an 'anti-rape' film or even a feminist statement, and I just have to chime in on the galling hypocrisy of these claims.
First of all, what do we see on the cover of this movie? That's right: a shapely woman's behind. Whether it was Zarchi's attempt to make an anti-rape statement - and I absolutely don't believe it was - is entirely beside the point. The film is marketing sex and the titillation of sexual assault and the material is so graphic (everything but actual penetration is shown) that NO ONE but the hard core exploitation crowd will enjoy it.
The rape(s) in the film is uncomfortable, brutal and hard to watch. There's something to be said for presenting a horrible crime in such a brutal light, but there was no reason for this scene to go on for seemingly 30 minutes, none. There was also little character development of the victim and only one of the rapists is slightly developed (mere moments before he's murdered) so the scene isn't at all engaging on an emotional level. Really, it's just presented for the sake of showing extreme sexual violence and you can tell by the movies ISOYG is associated with on IMDb (Caligula, Cannibal Ferox, etc.) that it attracts only the exploitation crowd.
Finally, a few reviewers have commended Zarchi's so-called documentary style and lack of a soundtrack. But considering how inept everything else in the film is (acting, script, etc.) I suspect these were financial decisions and the film looks like a documentary because he literally stationed a camera and let his porn-caliber actors do their thing.
I'm not going to get all up on my high horse talking about the content of ISOYG. I'm all for exploitation / horror and love video nasties. In fact, I'm giving this movie three stars only because it truly does push the envelope so much further than some other films. However, it's also poorly made and after the rape occurs, just downright boring for the rest of the film as we watch a bunch of ho-hum, mostly gore-less murders and wait for the credits to roll.
This is probably worth watching once if you're a hardcore 70s exploitation fan but I'm telling you, the movie is overall pretty bad and not really worth its notorious reputation.