Just got back from vacations and I watched episode 17 and 18 saturday. I watched a couple of youtube video reactions to the episodes but I didn't read anything from this thread about them. So here are my thoughts.
Basicaly it felt like episode 17 was the ending of season 3 that the fans wanted and episode 18 could be the beginning of a fourth season or a way for Lynch to tell the audience that nothing ever ends (like season 2 by the way).
Lynch and Frost gave us a lot of what the audience wanted to see in 17 (minus a lot of things too...) and gave us more weird things in the last episode.
Those episodes are amazing Twin Peaks episodes BUT I can see why some fans are frustrated because no one loves cliffhangers everywhere on the last episode of a season that could be the last season ever...
But like I said the end of season 2 was even more "WTF?" to me.
But if we take the point of view that there will not be a fourth season then we have to see what we got as the definitive "wrap up" of Twin Peaks. Some things looks complete, some don't and some are just left for us to think about and it would not matter if there's a fourth season or not.
The main example would be Audrey Horne's story. When we start to see her in season 3 the audience obviously wants to believe that she's linked to the main story, somehow. Maybe she's "the dreamer"? Maybe Coop will save her from a mental prison? But nope. To me her story is her "return" (to consciousness?) as much as the whole season is about the return of Cooper and, in the very last shot, the return of Laura Palmer (her scream). Lynch is showing a main story AND various stories about people that may or may not wrap up by the end of the season. We knew it would be like that with Lynch, and it is.
Now the fun beginnins... Is Audrey waking up in the same reality as Cooper/Richard and Laura/Carrie? Some fans are saying that they are now in our world. The real world. Will Cooper now have to meet David Lynch in person (who would no be Gordon Cole anymore) to ask him to "dream" a happy ending? Lol, Lynch being the dreamer after all.
We can see the last episode as a way to tell that the battle of Cooper against evil will never ends, I guess, but until a fourth season is annouced I can live with that cool episode 17 concluding the main story and that episode 18 showing that there could be other Twin Peaks along the road, even without Lynch on command by the way, because Dale and Laura could be seen as not on "David Lynch's Twin Peaks" anymore in the end.