It's been cut and edited to sort of be it's own thing.
There's no narrative it is entirely disconnected moments but rather than just show the scenes Lynch has cut in bits of the movie, added new transitions and stuff. It's a pretty engaging watch if you're a fan.

In the same way you could start Breaking Bad at season 3. You'll probably find some entertainment there but also you're joining an ongoing story in media res, you'll not be getting the full experience

Given how much of the first 2 episodes were devoted to non familiar stuff it makes sense to lengthen the episode to lessen the complaints about it not just being the old gang again..

The episode suggested there may have been two arms, the original and an evil doppelganger. That would align with the original series where sometimes he seems to be helpful, other times not. I think he has a line in the final episode along the lines of "next time you see me it won't be me" (and then obviously in this…

The line the tree thing speaks is also exactly the same of a line the Dwarf gives in FWWM. And yeah think it's supposed to be some sort of manifestation of Mike's arm, there's a scene in FWWM where he places his hand where Mike's arm would be and they speak in unison

Interviews with cast members have suggested that aging / the passage of time is a key theme to this new series

They seemed to be working together in FWWM - they both take Leland's garmonbozia from BOB at the end

Always thought the Log contained the spirit of her dead husbad, as the original series does seem to suggest the spirits of people can get trapped in wood..

I think that was also a callback to the pilot where the infamous "Frank Silva reflection is captured in mirror, he becomes BOB" happens. The TV show was reflected in the mirror behind her, thus we Sarah Palmer is foreground with a predator's reflection in the background, again…

Twin Peaks is filled with the trademark Lynch slow pacing. The opening to season 2. The scene with the bank teller in the last episode. It's suspense building / deliberately off putting

I took it to be part of the ritual Bob uses to possess Laura in the train cart.
They also kind of reference Bob as fire (particularly in the film, talking about burning of innocence and the like). So possession is "fire, walk with me"

Before it basically showed up whenever Sarah Palmer was drugged (before Maddie is killed and in the film when Leland's having with way with Laura). But yeah now it could be that it also is an omen of death..

I think maybe they want to make the death stick for a while at least to emphasise his heroic sacrifice, which does make sense it was a great arc for the character (and I did like how they linked that in here).
But then again he's too fun to not have around, although I'd love it if they just kept plucking him from a…

It's all pretty poorly written. I think Savitar comes out of the speed force in 2017 after being trapped in 2021 (or whatever it was), as he's pissed at Barry partly for being trapped so long (he references his prison many times)

Plus surely context? This scene felt akin to sexualised shots of naked women in other stuff (including Game of Thrones) whereas naked Hodor running in and out in a comic moment didn't exactly feel like it was there to appeal to those who like Peni..

Isn't it that the Legends prevented Doomworld from ever happening by going back in time to when Thawne used the Spear?
Thus the Dahrk they brought back to WWI was pre-Doomworld Dahrk?
Possibly.

I don't know much about production schedules but surely this episode would've been written a while before Amnesia Barry episode aired and possibly before the musical episode aired too.

Spoiler tags perhaps?
(Admittedly a little late in the day to point this out)

That's absolutely what they were inferring (well the first part at least). Plus also sowing the seeds for her to become an ally..

They're just there to provide bodies for fight scenes next week. Plus I think masked fighters is just a necessary part of Arrow (most likely as it means they can re-use the same stunt guys over and over) like GHOSTs or Slade's army or whatever.