I thought the first 20-30mins of the episode were great. Really great. The North was being absolutely smashed and it was really sad to see all the heroes being brutally beaten: Brienne was surrounded by undead, being chewed on etc.; Grey Worm knew the battle was lost; Tormund was overwhelmed; Sansa fled to the crypts and was just like 'whelp, we're fucked'. It's Game of Thrones, so I assumed it was going to be somewhat realistic (yes I know there's magic and dragons), but as main characters kept on miraculously surviving (Samwell Tarly, really?), I started to get a bit bored and the impact lessened.
If this was an episode (or a film even) of some other fantasy show, like LOTR or something, then I would have absolutely 100% enjoyed it. We all knew Frodo was going to win in LOTR and Aragorn, Legolas and Gimli would be ok and that's fine. In GoT we all knew Ned Stark was going to be ok and then he got fucking beheaded.
It was an exciting episode with a very satisfying ending where all our heroes survived and the baddies were beaten at the last moment (it reminded me a lot of the end of The Phantom Menace) and that, for me, is not how Game of Thrones should be and I'd be willing to bet that it's not how the book is going to handle it.