In screenplays, the unreliable narrator usually constructs a false narrative, and the audience gets into the false story as if it were real. In The Usual Suspects, you have the heist story with a collective protagonist, and the real story, which consists of Verbal Kint constructing the fake story. Similar situation in Fallen (“This is the story of how I nearly died”). The fake and real stories take place simultaneously, but the audience doesn’t know the fake story is fake until it’s concluded (as Scott points out). In both movies, the Nemesis of the fake story turns out to be the protagonist of the real one.

There are scripts with ironic narrators — characters (usually protagonists) whose opinions of themselves are grossly overinflated or romanticized, e.g. Badlands. In a case like this, the audience does NOT get into the story as deeply as they would with a non-ironic narrator, but stay a little detached, judging the protagonist more than rooting for her.