I watched an advance screening: not very good, unfortunately (spoilers)
* This film introduces too many new characters, each with their own mysterious backstories, a lot of whom are superfluous to the action. For example, Nagini is introduced as Credence's best friend, which happened some time in the six months between the events of the two films. That is her entire role in this film.
* Jacob and Queenie were easily the best characters in the first "Fantastic Beasts" so the sequel ... uh ... separates them by having Queenie join Grindelwald with very little persuasion needed (she's upset that she isn't allowed to marry Jacob by the wizarding community). Instead we get more of Newt and his love triangle with the equally boring Tina and a new character, Leta Lestrange, who gets an entire backstory and flashbacks ... and then gets killed off.
* There is a LOT of dull exposition about heretofore unheard of curses and family histories.
* There's also a distracting amount of CGI set pieces. It shouldn't be a problem for this particular series but, not only is there CGI in every scene, the action-sequences (which are all big and explosive) are filmed in such a chaotic fashion that it's hard to tell what is happening.
* Johnny Depp's Grindelwald is supposed to be an ultra-charismatic warrior wizard - so persuasive, in fact, that he's not even allowed to talk to people while in jail. This is undermined by ... Johnny Depp. He's miscast and the albino make-up and weird eye doesn't help. He's not seductive at all.
* The twist that Credence is Albus Dumbledore's long lost brother just seemed cheap and tacked-on. We needed the entire sub-plot with Leta LeStrange and her long-lost half-brother for that???
* The only implication of any romance between Dumbledore and Grindelwald was a magical blood-pact between two men who shared the same ideology and vowed never to battle each other i.e. a split second of touching hands.
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