[QUOTE=BrainGlutton]
Then what was the series finale?
[/QUOTE]
There wasn’t one.
You have to understand the difference: A season finale is often a cliffhanger, setting up situations that will be resolved the next year. The classic example is “Who Killed JR?” on Dallas. Or the various ST:TNG season finales (e.g., when Picard was taken over by the Borg).
A series finale ties up loose ends and lets us say goodbye to the characters. The recent West Wing series finale is an example, as is the final episode of Arrested Development.
The basic difference is that for a season finale, the production team assumes the show will be renewed; while for a series finale, the production team assumes the show will be cancelled.
Sometimes they’re wrong: Sledge Hammer had what they thought would be a series finale by blowing up the city and all the stars. When the show was renewed, they had to fix it (by billing it Sledge Hammer: The Early Years. The opposite happens more often: Everyone on Alien Nation (and Galaxy Quest
) thought it was going to be renewed, so they ended with a cliffhanger. When it was cancelled, the series ended in limbo (though they did some TV movies to tie it up).
Now, for Twin Peaks, they were assuming the show would be renewed, so they wrote a cliffhanger ending. The third season would have dealt with that issue, but the show was cancelled. It’s quite clear they didn’t expect the last scene to be the final word, and it would have been a nice jumping off point for plots.
Re: Second Season
I do think the show flagged after the mystery was revealed, but after a few weeks it began to find its way in new directions. I don’t think it reached the level of the early episodes, but it was still great television once you got past the slow stretch.
But Twin Peaks was going to be doomed by its own complexity. If you didn’t catch it from the start, it was hard to get into it, and as people grew tired of it and left, few new viewers tuned in.