TIL "&" and "and" mean different things in movie credits. Two writers' names joined with "&" means they collaborated, while "and" means they worked on the script at different times.

Some other bits I've heard or know (not sure which):

If an actor is "introduced", as in the credits specifically say, "Introducing <actor name>", that's the first "major" role they've had. Less used nowadays. Never used in closing credits, always opening.

If an actor is introduced as a "Special Guest", "Special Appearance", or some other honorific, or if they character's name is displayed, that usually means either a big-name actor is guest starring, or they're a recurring but not main character (for example I think Michelle Forbes was always in the credits in ST:TNG as "Michelle Forbes as Ensign Ro Laren), or alternately if they've specifically negotiated some deal where that's how their name shows up (again, typically need to be a "big enough" name to negotiate this, it'll be part of the contract). Regular, main characters are almost always just listed as their (actor) name.

The last 3 names in the opening credits, in order, unless there's been some special negotiation will be: Producer(s), Writer(s), Director(s).

Opening credits (and some of their contents, like the above ordering) are or used to be a requirement of the Director's Guild. Lucas was famously fined by the union for opening Star Wars with a crawl instead of credits.

It's somewhat normal for "surprise" characters in a TV show to not have their actor names in the opening credits, or if it is they structure it such that their name shows up after their introduction if it happens early enough in the episode, so as not to spoil the surprise.

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