Knock Knock is a remake of the 1977 cult film Death Game. That one co-starred Colleen Camp as one of the temptresses. Camp is on-hand here, both as a producer and in a cameo. I've not seen the original, so you'll need to look elsewhere for comparisons. The hook is pretty irresistible: what's a guy to do when the family's away and two gorgeous, young women show up needing assistance? The set-up is fun and sexy. Genesis (Lorenzo Izzo) and Bel (Ana de Armas) butter Evan up with compliments. Once they change into robes after tossing their soaking clothes in the dryer, their small talk turns almost shockingly frank. Both girls begin sharing details about their sex lives. By the time they're urging him to partake in a threesome, he caves into the undeniable pressure.
The rest of Knock Knock plays out like a cheating man's worst nightmare. Genesis and Bel quickly reveal themselves to be highly manipulative and apparently psychotic. They also reveal themselves to be underage. From this point on, Roth (who also co-wrote) could've taken the story just about anywhere. The problem is, he doesn't take it anywhere remotely interesting. This isn't a horror film nor is it torture porn, so don't expect things to get too wild. Basically, Genesis and Bel aim to make Evan pay—partly via physical pain (and a death threat is definitely part of the plan), but mainly on a psychological level. Unfortunately, neither Genesis or Bel are fleshed out into full-bodied characters. This is especially disappointing in light of some of Bel's obsessions, which indicate a highly troubled past rife with abuse.
It's also worth pointing out that Keanu Reeves comes across as conspicuously artificial in this role, the follow up to his genuinely impressive comeback in John Wick. Whether he's overplaying the "fun-loving dad" role or robotically shouting insults at Genesis and Bel, Reeves just seems phony and uncommitted.
Weirdly inconsistent 1080p presentation on the new Blu-ray edition, which is certainly atypical for Lionsgate releases. Most of it is fine, but there's some instances of banding that are noticeable enough to cause a distraction. Much more satisfying is the DTS-HD MA 5.1 surround mix. Early on, during a scene set inside Evan's house on a rainy night, the rain effects in the surrounds were realistic enough that I initially wondered if it was actual rain I was hearing. No problems with dialogue or the balance between music and effects.
Knock Knock is graced by a director's commentary, a featurette, deleted scenes, and an alternate ending. Don't go into this film expecting a gore-fest from Eli Roth. This is a psychological thriller that, while watchable (thanks to Lorenzo Izzo and Ana de Armas), skimps on the psychology.