I have been digesting the episode for a while, and I have a bit of time so here's my take on the episode:
It was bloomin' brilliant, but also flawed at the same time.
Despite the awful encoding on Sky making it look like mud, it was visually excellent. The dark aesthetic was used to brilliant affect, and it was overall a visual treat. The sound track was amazing. I had hoped for a different outcome from the battle, but I'm not so sad with the Arya outcome. With the benefit of hindsight you can see all the things leading up to it, and it makes perfect sense with the writing so far. From the fuss made about Catspaw, including Sam reading about it in the citadel, to the hints in the prophecies, the build up of Arya's skills, the same move used to kill him shown off a few episodes earlier, and the in-episode reminder about her stealthy side, it fits together really well. Of the ways that the Night King could be taken down and end everything, it was one of the best. It also makes sense that the story is "really" about the throne of the Seven Kingdoms.
On the other hand, the absolute tactical stupidity of the "Allies" was almost unbearable, from the amazing incompetence of the initial setup to the multiple failures to think ahead, it seemed like it was a plan dreamed up by someone who'd never even seen a battle, yet alone considered the nature of the threat they were facing. I can forgive overlooking the potential threat of the Crypt but to not even post some guards to protect them is ridiculous. Meanwhile they stake everything on beating the Night King with the Bran-baited trap, but didn't even think to put in place a backup for dragonfire not doing the job. Why was no-one placed there with Valerian steel or dragonglass weapons? Why not hide a squadron of archers with dragonglass tipped arrows on the walls? Something other than: oh poop, he isn't dead, we got nothing. Theon's last stand was narratively nicely done, but why-oh-why wouldn't he know how to charge with a spear? I'd like a charge, but running with a spear at someone isn't a charge, it's the rookie mistake of someone who needs to be taught to stick them with the pointy end. Why didn't he hold the spear closer to the butt end and drop into a thrust at the end? It's a spear! The damn point is that the point is that the stabby bit stays a goodly distance from you!
Then there's the ridiculous levels of should-be-dead on show. Yes, I know it's not that bad by the standards of normal TV and film but GoT was at its best precisely because it didn't follow those rules. To some extent, I suppose, it's because the show is now focusing on the characters who've always had the most plot protection. Show!Dany is less ridiculous than book!Dany but she still gets away - repeatedly - with stuff that would have ended other characters or at least spoiled their plans throughout every season. Several times we see characters swamped in one scene and apparently fine the next. Yes, the death toll was heavy, but it was an unsurprising cast of deaths.
I watched Endgame last night, having watched GoT in the morning and - without spoilers - it really sells its big fight scenes so much better. The Night King, a threat built up over seasons, should not have gone down so easily. Yes, the set up was there for Arya getting the kill, but he needed to be seen to win more on the way in. Sure, he took the dragonfire and kept on coming - something which was, by the way, nicely foreshadowed in earlier episodes - but he took a beating on his dragon and never even needed to draw his sword. I'd have liked to see him battle someone with a Valerian Steel sword - Jorah would be the obvious choice - and crush them underfoot, or something, anything, to make the personal victory over him feel more hard one.
Plotwise, I really dislike the overworn cut-off-the-head-and-the-rest-die trope. It's just tired at this stage. I'd have much rather they had a cleverer means of beating him than just "kill the leader". Even the rest of the White Walkers surviving would have made a big difference. Let them escape to fight another day, and things stay interesting. I'm also not mad-keen on resolving it at all at this stage. I'd have liked to see them lose this battle, and take a rag tag force south to make another stand, perhaps even with Cersei losing Kings Landing as a result of her refusal to join the fight. But, that said, I'll be happy enough if it feels like there are consequences for this battle. The entire Dothraki army gone. The Unsullied more or less wiped out. The force of the North decimated. The dragons alive but injured. That should have serious consequences for Dany's ambitions. I'd also take some more interesting stuff happening following on from Bran and the Night King; although I hope they don't succumb to their tendency to overexplain and give motivations or similar to the Night King. None-the-less, Game of Thrones has always been surprisingly grounded for a fantasy show, the main conflicts have always been human and political, so I do think that it needed to come down to a human conflict in the end. My hope that Dany will finally, finally die from one of the so, so, so many immensely dumb things she does is looking less likely all the time so I'm pretty sure that she'll take the throne of Westeros one way or another.
Overall, it feels like Game of Thrones has lost some of what made it such an interesting, unique, show and become a damn well made fantasy show instead. Now, I like a damn well made fantasy show so I'm still loving it, but I still get a little feeling that it could be better. I remain hopeful that we'll see an ending that is worthy of the build-up
