Andrew Clark’s review published on Letterboxd:
Wan, bro, you are crazy for this one! MALIGNANT is an extremely goofy theme park ride. The great thing about it, though, is that Wan knows just because he's making a trashy, violent horror flick, doesn't mean he has to be out to lunch on the execution. His camera is assured, basically the equivalent of a good friend elbowing you in the ribs during the proceedings and waggling it's eyebrows. He's using all the tricks and traps in the horror stable to often great effect, with some sublime lighting and wonderful production design and practical FX.
One of my favorite Wan horror tricks is how effectively he frames light and shadow to create caverns of darkness surrounding little pinpricks of light around his characters, or whatever the operative focus of the scene is. Wan knows when it's appropriate to set conditions and design in the "real world" and when it's best to let abstraction and fantastical mise-en-scene do the heavy lifting. It's an absent skill from a lot of contemporary filmmakers toolbox's, I would say. We find ourselves in a period of time where plenty of directors seem like they are just interested in pointing a camera in order to communicate information, whereas Wan understands how important it is to communicate a feeling.
There is a twist and it is fairly obvious, which I think Wan is aware of, so in order to make up for it he goes well and truly off-the-rails. You can tell my guy went and made some action blockbusters since his last horror foray, and enjoys making use of some of those proclivities and skills here. Which is sort of too bad, because the lovely horror bits are absent from the final third of the movie. That said, there's much to enjoy in this fun and dumb movie. Welcome back to the genre, Mr. Wan.