I fear I may be turning into some sort of DC fanboy because... I thought this was great.
Like with 'Shazam! Fury of the Gods', I was not expecting much from these DCEU films as I only decided to watch them so I could catch up on this universe before the 'Aquaman and the Lost Kingdom' finale next month. I guess I was subconsciously anticipating these to be as flat as a pancake due to the suits upstairs focusing on the upcoming DCU. Yet, I've had a terrific time thus far - 'Blue Beetle' pending.
As for this film itself, I'm not someone who has any interest in comic books so my only knowledge comes directly from the films. All I knew beforehand was the rather dodgy life of Ezra Miller (just look at their Wikipedia!) apparently affecting production. That's a lot of words to simply say that I have no clue how well of an adaptation this is from the comics, though simply as a film it give me entertainment, it really did.
'The Flash' features a strong performance from Miller, who portrays the aforementioned with quality throughout. I don't remember Barry Allen from the other DCEU flicks, so I'm pleased to have something memorable from the character with this. Elsewhere, Sasha Calle is very good as Supergirl, while Michael Keaton is much fun as Batman. There are some solid cameos in there too.
I will say that I personally would've shaved some of the run time, it does overrun ever so slighty. That is my only proper criticism though, given everything else from the story - which brings heart - to the special effects to whatever is done to a positive standard. Rating-wise, I've gone back and forth between 8/10 and 9/10 - it narrowly nabs the latter.