This was a very entertaining hour of TV. Very exciting, and I enjoyed a lot of the characterization. Q seemed delightfully unhinged and I'm curious where they're going to take it. Q was always able to be a good foil for JLP and this was very evident here. It's hard to comment on the grand design of this because it isn't apparent yet. I am nervous that there will be big letdown as so often happens but the setup so far is very fun.
They dystopia was a really "good" one. I think that Trek often employs the "evil/mirror universe version of characters are just sex crazed maniacs" trope too often and this was not that at all. Just a brutal look at what a fascist, cruel version of the UFP would be. It had a weight that is lacking in other Trek instances and I appreciated it.
I saw some criticisms upthread about how there was a lot of info dump in this episode. I mean...maybe...but in each instance of info dumb we were
shown things that established the wrongness of the timeline and the stakes involved. The Rios scene might seem unnecessary but there were shots of what were obviously WMD being used on Vulcan. A big deal! That was my biggest takeaway from the scene. JLP was a murderer in the past of this timeline, but the Confed was still actively engaged in active slaughter of those who are normally allies. Same thing with Elnor: he went from being lauded as the first fully Roman cadet last episode, and the inverse of that is him being hunted like an animal. The juxtaposition was effective and I didn't think it was wasted time.
I also liked how the Borg Queen was handled too. Even in a cage she was able to project menace and essentially stare into JLP and Seven's souls, so to speak. The "strange bedfellows" part of this is intriguing too, the Queen needs the crew and the crew needs the Queen and that is good drama for now.
There were a lot of great small touches in the episode. I honestly think my favorite was in President Seven's speech...Jeri Ryan did a great job of twitching her face and hesitating on the word "resistance" that immediately carried the weight and history of that word in the franchise and in that moment you can tell she realized that killing the Borg Queen was a morally abhorrent act, even if she wanted to do it. This is better characterization for Seven than last season. So much was communicated with just one word! I loved it.
The reprise of the FC Borg motif in a soft solo string instrument to signal the Queen brought low in this timeline was also very cool for me.
A nit to pick: JLP has his history wrong: it was not Kirk's Enterprise that slingshot around the sun, but the stolen BoP. [Edited to add: I am wrong about this and ashamed in my lapse of TOS knowledge

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I think it will be easier to judge this episode when the season is over but as a piece of setup, whose job it is to establish stakes and set the board for what's to come, and as a single episode of a television show it was very good. Tightly paced, exciting, and very watchable.