@shingro: I like to use the TV comparison when considering episodic content. Specifically, I like to use Buffy the Vampire Slayer, whose seasons are structured like a video game.

First episode of season: Big thing happens. Introduces new characters if appropriate. May introduce antagonist.

Follow with 8-10 standalone episodes of incidental things happening which may or may not affect the overarching narrative.

Midpoint of season: Big thing happens. If antagonist hasn’t been introduced yet, introduce antagonist. Major thing happens to main character and/or main character dies.

Follow with 8-10 standalone episodes of more incidental things happening with an undercurrent of “we’re building up to something big” — antagonist makes more regular appearances and starts doing more and more “major” things.

Season finale: Climactic battle between protagonist and antagonist. Story threads from season are wrapped up. Could potentially finish entire series here if necessary due to sense of closure.

Dragon Age II is structured like this. It works well.