You can tell that this sick exercise in grotesque sadism is an art film because it's filmed back to front.
That makes it easier to leave, if you're in a cinema, since you already know how it ends. But leaving, or switching off the DVD, would be wrong, because in Irreversible, director Gaspar Noe has three VERY IMPORTANT messages to tell us.
Firstly, no matter what quantum theory or Stephen Hawking may say, time and actions are IRREVERSIBLE. What's been done can't be undone. This is Gaspard's shocking theory. Don't let anyone tell you different.
Secondly, brutal prolonged anal rape followed by face-destroying bashing and attempted murder is wrong. I know that for some people this may come as a shock, but it really is wrong; except in many countries where it's a normal part of daily life.
Thirdly, you should not seek revenge when the girl you love is brutally raped and battered. You, or your best friend, may end up brutally battering and murdering the wrong person. Yes, another surprise from the very surprising Gaspar Noe, the director who is not afraid to challenge our core beliefs that rape and vengeance are OK.
So it's clear that this is a VERY IMPORTANT MOVIE. As well as filming it backwards in time, the importance of the movie is stressed by it being filmed by a handheld camera which rotates as crazily as an out-of-control computer game, and by the use of special effects which seem straight out of the latest X-box treat.
Alex (Monica Belluci) is the victim in this movie; her avenging angels are her lover Marcus (Vincent Cassel, who voiced Monsieur Hood in Shrek) and her former husband and lover's best friend Pierre (Albert Dupontel).
I'd earnestly recommend viewing this movie if you did not realise that time flows forward and that events can't be changed, or if you have not yet been brought to believe that brutal rape and violence are on the whole not acceptable in this society.
If either of those conditions apply, then this movie may change your life, or else have no effect at all. The latter will probably prove true, but you may as well give it a try, if your institution has DVD viewing facilities. For the rest of us, there's every reason to give this exercise in artistic brutality a miss.
This is a VERY IMPORTANT MOVIE and our sicko censors who don't appreciate the beauty of extreme violence have refused to give it a 'G' certificate.
This means pre-schoolers will be denied the chance to learn Gaspar Noe's essential verities. These things are best taught young. It's too late for the rest of us, so if you're old enough to read this, give this one a miss.