Fight Club, Se7en and Zodiac take a shit on it.
Fincher went around spouting all sorts of stuff about how it was unconventional and how the characters could live without each other's love. I then get one of the most conventional love films I've ever seen/Forrest Gump.
Oh these fucking Forest Gump comparisons really bloody annoy me. The only similarity is the journey through history, which in Gump is used as a joke of "Hey, look at what the moron can do" and in Button is to show a passage of time. Button is a love story, Gump is a dangerous ode to conformity and subservience.
Now to the point. It's a conventional film but the message is crystallised through the brilliant idea of someone moving backwards through life. Almost everything in Button is relateable, growing up awkwardly, not being accepted, your first love, letting go of them, moving on, watching the people you love die and get older, not being ready for
that relationship, sacrificing yourself for your children. Aging backwards is just a framing device to show all these things off. BB could be a normal child, things would happen the same, it just wouldn't have the same effect on the audience.
So in brief, great film, 9/10 but if you're marking of 5 then 5 is justified. The only thing that annoying me was the hummingbird.