Michael Sicinski’s review published on Letterboxd :
Truly, deeply ambivalent. I can understand being mesmerized by the sheer beauty of the thing. I mean, I simply can't think of any other films that remotely look, think, or operate like this. The psychedelic Frazetta poster aesthetic is a bit like the saturated crimsons and cobalts of Italian horror dispersed with a medicine dropper, swirling and curling into a kind of liquid vapor.
It's all in service to a two-tiered system of destruction, first some heavy metal Lovecraftian beings straight out of Hellraiser, and then a sort of Manson Family manqué who are played mostly for tonal disruption, sad and pathetic one moment, vicious the next. And at the center or it all are Red (Nicolas Cage) and Mandy (Andrea Riseborough), two relative ciphers whose idyllic love affair in the woods we are supposed to care about mostly because it is the only remotely human thing for miles.
Tedious as hell for the first 40 minutes, Mandy picks up once The Deed is done and Cage turns into a revenge-seeking killing machine. But what does it say that the main female character is a mere pretext, serving her narrative function only once she's dead? There's a grunting neanderthal quality to the whole affair, gussied up, as metal so often is, with fillips of dazzling color and style -- the light that reflects off a studded belt, the clanking sheen of hand-forged weaponry.
One can certainly admire the Wisdom of the Ancients while seeing right through it. Mandy strives to overcome irony, but it points to a place we can never return, nor should we.