I was impressed by the beautiful cinematography by Aldo Scavarda, but I wasn't all pleased by Antonioni's too laid back and sloppy direction. And not to mention the technical parts, shadow of the camera in many sequences, too obvious lighting and very poor sound dubbing (a particular Italian treat from the past).
Still, there is something very captivating about 'L'avventura'. Antonioni is best when his characters are alone, doing jovial or unusual things, making grimmases.
The first act of the film is most interesting, especially because of the dialogues on the boat. Later, it gets a little boring, as if Antonioni wasn't too sure which way to go. Also, the plot is somewhat dull, idiosyncratic and underdeveloped.
I cannot hide that I am somewhat disappointed. I guess, I expected much more.