Verdict:

Casablanca is a difficult movie to review because there is nothing particularly wrong with it, but also nothing particularly excellent. It is more about whether or not you like its style.
Its style is very misty-eyed. The insisting violin vibrato in the high register tries to cut into your heart, as the main hero talks harshly to the damsel, but inside we all know that he really loves her. This film is a lady who sighs as she holds her wrist against her forehead in a gesture of fainting.
The film deals with the events of a refugee crisis and anti-Nazi resistance, but the movie is really about the relationship and conversations between the main characters, and to its credit those interactions are good. The film explores the sacrifice and internal turmoil of the two leads in the situation they found themselves in.
The movie is the set for 2 heavyweights of their time: Humphrey Bogart and Ingrid Bergman. If you know that guy, then there is nothing for me to say, as you already know what his performance will be like, but if this is your first introduction to the guy, Bogart is the poster child for over-stylised acting that was so persistent in the first part of the 20th century, though this is probably one of his best roles, requiring the tortured-poet attitude, with a dash of cynicism and vulnerability, which no one can deliver better than him. But it’s like the creators wrote the main character to be Humphrey Bogart. An actor should bend himself to become the character and not the other way around. Bergman is far more interesting. Her facial expressions speak volumes, and her method is much more subtle. A camera hangs on her face for almost a minute straight and she is able to fill that time with life. The most interesting performance is probably by Claude Rains, who plays an opportunistic French officer.
Some of the dialogue can be witty. I am not sure I understand why certain lines became famous. “Here’s looking at you” seems witless and artificial. It’s like when a teenager trries to make a catch phrase stick. When the writing is not sappy and not trying to be cool, that is when it is at its best.
The fog and shadows provide a moody atmosphere. Framing is used to show distance between characters, until those barriers are broken down. It is of course an excellently shot film.
Casablanca is competently made but there is nothing that strikes as particularly special about this film. There are worse ways to spend an evening than watching a good quality film, but all the hype that makes this movie out to be the best ever is really unnecessary, and if you dislike the overacting of the 40’s, this may be a difficult watch.