Not a perfect episode - but still very satisfying and enjoyable (at least for me).
Best parts:
1. The entire first 30 minutes. Really did a phenomenal job of setting up the battle and making you feel the anxiety and weight of the moment and the characters. Melisandre riding in and lighting the Dorthraki's arakh's on fire was visually stunning. Seeing them ride off and the fire extinguished was both spectacular and anxiety provoking at once (all in the Jaws sort of way - where you don't actually see the shark).
2. Arya's scenes. Absolutely loved how they tied her prophecy (of closing blue eyes) into her killing the Night King. One of those moments that makes you wonder how you missed that when it was first said years ago (there were theories that the prophecy was she would kill Cersei -- since she has green eyes, but I don't recall any theories of her killing the NK as part of that prophecy). Also - the scene where she is being stalked in the library was another nail-biter and really well executed. Reminded me a bit of World War Z (a bunch of scenes here obviously did), where Brad Pitt is trying to get to the room with the viruses and avoid the zombies toward the end.
3. Many of the scenes where they focused on the individual's plight - rather than the overall battle. Lyanna Mormont killing the giant, Theon defending Bran, Jon trying to get to Bran but being held off by Viserion, Sansa and Tyrion in the crypt, the Hound going to save Arya - all really well executed.
Just okay:
1. The actual battle. Did a great job of showing the chaos and confusion of fighting this type of battle at night (and being overrun by sheer numbers), but I agree that the darkness and speed of the whole thing made it a bit tough to follow and appreciate (beyond getting the confusion that they were likely trying to depict) and there were certainly some tactical WTFs.
2. While I loved how they set up Arya to be the savior, I thought her actual saving moment could've been better crafted/developed using her prior learned skills (maybe using the darkness of the whole battle to her advantage somehow). And, if you are going to jump out of a tree to attack him in a stealth like manner, at least don't scream while you're doing it.
Somewhat disappointed:
1. 8 seasons and 70ish episodes of developing this entire story line over the NK and the battle of the dead and in the end, it's all neatly and cleanly resolved in 1 episode. Just feels sort of shallow. And the NK's motivations still seem unclear and weakly developed.
2. Top 10 important characters in this episode: Jon, Dany, Arya, Sansa, Bran, Jaime, Brienne, Sam, Davos, Tyrion. They all come out unscathed. Just not believable given the scale of this thing (especially Jaime and Brienne who seemed to be fighting an endless horde of zombies for the entire time).