The color is very lifelike in this film. You can see how color adds a whole new dimension of reality to the picture if done right. It provides the context to differentiate between objects in a space almost serving the same effect as the introduction and development of shallow focus to literally focus your attention on particular characters or objects. Well, color can do the same. If a character is wearing a red coat you can spot them in a crowd of dozens. Other colors just draw your attention and focus your gaze as a viewer. Powell and Pressburger really advance the use of color naturalistically and to great storytelling effect in their films.
David Niven is great in this movie. He shines as an actor and the dialogue is wonderful. The sets are fantastic as well, really grabbing your eye and elevating the ideas behind each scene and moment in terms of not just his progression towards death but also the recreation of his life's key moments throughout the film.
The biggest achievement of this film is it's use of color. By creating more realistic hues films can start to feel a whole lot more like captured reality rather than just artificial coloring that it looked like in say The Adventures of Robin Hood. You see the potential for color cinema to be the norm in the future with this film and the power that color adds to narrative storytelling.