A great film.
From Roger Ebert's review:
"Standing back from the film and what it expects us to think, I see them engaged not in romance or theft, but in behavior. They're intoxicated by their personal styles. Styles learned in the movies, and from radio and the detective magazines. It's as if they were invented by Ben Hecht through his crime dialogue. Walter and Phyllis are pulp characters with little psychological depth, and that's the way Billy Wilder wants it. His best films are sardonic comedies, and in this one, Phyllis and Walter play a bad joke on themselves."
The excerpt above from Ebert's review should give those who didn't like and "get" the film a clue as to why it is the way it is. The acting, the line delivery, the tone of the film, and everything about it is of its time. Roger is exactly right when he says that Walter and Phyllis are pulp characters. They're not supposed to come off as real to life people. Wilder has made this film and depicted these characters as fatalistic caricatures caught up in a pulp magazine detective story. If you expected realism you missed the point and unfortunately then can't enjoy the intended effect. Also, as Ebert points out, these characters are to be viewed through a dark, sardonic, comedic lens.
If you don't understand that the filmmakers (director and writers) were trying (successfully) to depict a world where the characters are fated to fail and couldn't help but speak like they were stuck in a 1940s pulp fiction magazine story then of course you won't like it.
What you don't realize is that this is the way they are supposed to behave and talk, and that everything about this excellent film is executed the way it is so as to shine a light on how people in the real world can be swept up by the fates both of their inescapable character traits, and the nature of the time and place they are caught up in.
Sometimes art is not meant to look like the real world so that we can see the real world in a different light and enjoy the artist's creation because its vision is merely a metaphor for reality.
This is a great film noir, one of the best, and if you think that all the best movies should look as much like reality as possible then you should probably not watch movies anymore because you won't be able to enjoy some of the greatest artistic masterpieces ever put to celluloid.
Ending was hell good.
10/10