Codes and Conventions of Opening Sequences

From my research on opening sequences, it is clear to see that the codes and conventions opening sequences are to:

- Introduce the narrative. 
Saturday Night Fever: the non-diegetic sound introduces the idea of disco, and the characters footsteps are in time with the music, suggesting he is in tune with this theme.
Inception: introduces the genre of thriller, as the audience is shown as little as possible to provoke thoughtfulness.
Mission Impossible: the mise-en-scene, like the inclusion of a burning fuse, shows what kind of events are to take place in the movie.
Die Hard: the hint that the main character is a cop connotes skill and violence that will come in handy later on in the movie.
Children of Men: the news report successfully introduces the narrative of everyone being older and also sets the time period. 

- Introduce the main character.
Saturday Night Fever: the entire opening scene revolves around the journey of the one main character.
Inception: the first face we see on the screen is that of the main character, and he's also the source of mystery in this opening scene.  
Mission Impossible: the faces of recurring characters show up on the screen multiple times, allowing us to recognise them late on. 
Die Hard: a conversation takes place between the main character and another man, and the camera then follows the main character, showing his importance. Children of Men: the main character walks against others and the camera follows him, which makes him stand out. 
- Use a montage (often).
This is displayed in Saturday Night Fever, Inception and Mission Impossible.
- Use little dialogue (often).
This is displayed in Saturday Night Fever, Inception, Mission Impossible and Children of Men.