Scott Wise’s review published on Letterboxd :
This is the best film in the X-Men franchise to date, and may be the best X-Men film we ever get. Unfortunately, that's not necessarily a good thing.
Ignoring the logical trappings of time travel, it's actually a remarkably simple narrative, with a few milestone set pieces but only one core point which its plot is driving towards. That's a blessing and a curse, because while it doesn't feel overly long, neither does it feel entirely fulfilling.
In the X-Men universe, it gets a lot right. It bridges the storylines and characters of the scattershot timelines of previous films, and does so remarkably well. Its characters are all true to their roots while remaining incredibly well-realized onscreen, with amazing action sequences that are fantastically choreographed. Visual effects and acting skills are never at fault, and with Singer back in the saddle it feels clean and concise. It’s also markedly dark, which is something this genre greatly benefits from if done right (here, I’d say it does).
But it's not all roses.
We are introduced to a compelling new character, Quicksilver, who is amazingly well-executed (and who is given a show-stealing scene in the middle of the film). Actually, he’s better realized than I thought a faster-than-the-eye character ever could be. And yet, after he is crucial to a single action set piece, he's effectively sidelined for the remainder of the narrative without much explanation.
The entire plot hinges on one premise: convince a character to change their mind. It’s a summer blockbuster, so we understand that the film is likely to go the satisfying route and deliver on that mission. So when it does, we’re not surprised, and the film doesn’t seem like it deserves to be rewarded for doing anything brave or challenging in its approach towards that goal. There are some cool new ideas in the micro – in characters, action scenes, even in twists to the canon storyline that only time-travel can afford – but never on the macro. So the overall effect is much like eating a buffet: a few things taste great, and you come away full, but you’re not truly satisfied.
And, it appears we’re never going to get a version of Beast that doesn’t look terrible in motion.
I will forever be especially hard on the X-Men franchise, because it was the one set of characters that I was especially connected to while growing up, saving coins for weeks to purchase whatever issues I could get my hands on. To his credit, Singer is able to realize these characters better than anyone to date, and with the more mature themes of this film they feel as though they are incredibly close to their full potential. He’s also able to convincingly ret-con out a number of poor decisions this franchise has made in previous films. And yet, there’s still a lot left on the table.