Sergejs Timonins’s review published on Letterboxd:
If you are a horror fan, go out and support our brother James Wan who just spent all his "Aquaman" and "Furious 7" studio credit on one batshit insane horror flick like no other! It has it all - giallo and 80-ies slashers, 90-ies supernatural cop shows and much more plays like feature length non-mythological "The X-Files" episode, sans Mulder & Scully, but done on "The Conjuring" technical level. And, above all, it's just SO. MUCH. FUN! (especially if you get all the homages)
If UPGRADE were a slasher-horror, it would be MALIGNANT.