"Play it again, Sam."
"You must remember this
A kiss is just a kiss
A sigh is just a sigh...
The fundamental things of life
As time goes by..."
Casablanca is a great film. Not argument on that. The question is what makes it so absolutely great? Umberto Eco says Casablanca is a great film because it incorporates, in some magical way, all kinds of movie plots and genres. It a mishmash of all kinds of movies, and works. He writes:
“… Forced to improvise a plot, the authors mixed in a little of everything, and everything they chose came from a repertoire of the tried and true. When the choice of the tried and true is limited, the result is a trite or mass-produced film, or simply kitsch. But when the tried and true repertoire is used wholesale, the result is an architecture like Gaudi's Sagrada Familia in Barcelona. There is a sense of dizziness, a stroke of brilliance...”
“…But usually to make a good story a single archetypal situation is enough. More than enough. Unhappy Love, for example, or Flight. But Casablanca is not satisfied with that: It uses them all. The city is the setting for a Passage, the passage to the Promised Land (or a Northwest Passage if you like). But to make the passage one must submit to a test, the Wait ("they wait and wait and wait," says the off-screen voice at the beginning). The passage from the waiting room to the Promised Land requires a Magic Key, the visa. It is around the winning of this Key that passions are unleashed. Money (which appears at various points, usually in the form of the Fatal Game, roulette) would seem to be the means for obtaining the Key. But eventually we discover that the Key can be obtained only through a Gift -- the gift of the visa, but also the gift Rick makes of his Desire by sacrificing himself For this is also the story of a round of Desires, only two of which are satisfied: that of Victor Laszlo, the purest of heroes, and that of the Bulgarian couple. All those whose passions are impure fail.”
“…Thus, we have another archetype: the Triumph of Purity. The impure do not reach the Promised Land; we lose sight of them before that. But they do achieve purity through sacrifice -- and this means Redemption. Rick is redeemed and so is the French police captain. We come to realize that underneath it all there are two Promised Lands: One is America (though for many it is a false goal), and the other is the Resistance -- the Holy War. That is where Victor has come from, and that is where Rick and the captain are going, to join de Gaulle.”
“…But precisely because all the archetypes are here, precisely because Casablanca cites countless other films, and each actor repeats a part played on other occasions, the resonance of intertextuality plays upon the spectator. Casablanca brings with it, like a trail of perfume, other situations that the viewer brings to bear on it quite readily, taking them without realizing it from films that only appeared later, such as To Have and Have Not, where Bogart actually plays a Hemingway hero, while here in Casablanca he already attracts Hemingwayesque connotations by the simple fact that Rick, so we are told, fought in Spain (and, like Malraux, helped the Chinese Revolution). Peter Lorre drags in reminiscences of Fritz Lang; Conrad Veidt envelops his German officer in a faint aroma of The Cabinet of Dr. Caligari -- he is not a ruthless, technological Nazi, but a nocturnal and diabolical Caesar.”
“…Thus Casablanca is not just one film. It is many films, an anthology. Made haphazardly, it probably made itself, if not actually against the will of its authors and actors, then at least beyond their control. And this is the reason it works, in spite of aesthetic theories and theories of film making.”
The full text of Uberto Eco article "Casablanca, or, The Clichés are Having a Ball" here.