Knock Knock 4K Blu-ray Movie

Rating summary

Movie		1.5
Video		0.0
Audio		4.5
Extras		3.0
Overall		2.0

Knock Knock 4K Blu-ray Movie Review

Reviewed by Jeffrey Kauffman October 30, 2025

Note: October's releases from Lionsgate Limited are another variant grab bag of formats and packaging options. Jacob's Ladder 4K offers 4K and 1080 discs in SteelBook packaging, Knock Knock 4K offers only a 4K disc in a DigiPack, and Lionsgate Limited continues with their curation of Vestron Video outings with Hider in the House, offered in 1080 only.

The Police may have made the term "synchronicity" recognizable to untold generations unacquainted with the venerable Carl Jung, but for those wanting a rather unexpectedly weird example of the phenomenon in Jung's original formulation, check out my opening paragraph of my Knock Knock Blu-ray review of Lionsgate's 1080 version released several years ago. Lionsgate is revisiting the title in 4K with two new supplements (both offered in UHD with HDR) along with "legacy supplements" and that aforementioned DigiPack.

The above linked review also provides plot information, a list of supplements on that release, and my reaction to the technical presentation.

Knock Knock 4K Blu-ray Movie, Video Quality 

Note: This release does not include a 1080 Blu-ray, so these screenshots are taken directly from the 4K UHD disc and downscaled to 1080 and SDR. Color space in particular is therefore not accurate, and I recommend those interested to look at some of the screenshots in our old Knock Knock Blu-ray review of Lionsgate's 1080 release for a probably better representation of the palette. Since this release does not include a 1080 disc, the 2K video score above has been intentionally left blank.

Knock, Knock is presented in 4K UHD courtesy of Lionsgate Films' Lionsgate Limited etailer with an HEVC / H.265 encoded 2160p transfer in 2.39:1. The brief but appealing Establishing Shot featurette with Eli Roth (listed below) actually shows him in the 4K mastering suite dealing with issues like brightness and grading on Knock, Knock, with an attendant interview featuring Roth waxing nerdily enthusiastic about 4K in general and 4K discs in particular. The good news is that all of the truly weird artifacting I mentioned in my old Knock Knock Blu-ray review has been ameliorated. The bad news is that this is probably even more "digital" looking than the old 1080 presentation. On the plus side of that particular equation is some really commendable clarity and outstanding detail levels, but there's just a kind of flat glossy quality that can't be denied. While nowhere near what can be seen on the 1080 version, that very digital quality probably aided and abetted by Dolby Vision / HDR tends to come close to some posterizing in some of the brightly lit moments (typically early on before the maelstrom of the young women hits). The HDR grades add a kind of sickly yellow look to a lot of the interior footage, but probably also offer a bit more shadow detail in some of the darkest moments.

Knock Knock 4K Blu-ray Movie, Audio Quality 

Maybe a little surprisingly, this 4K version has been granted a new Dolby Atmos mix which definitely improves the generally effective DTS-HD Master Audio 5.1 track that was on the old 1080 disc. The biggest consistent improvement here is probably with regard to the fun source cues, which pulse through the surround channels with considerable vigor throughout the story. As chaos unfolds, there's also clear engagement of the "traditional" surround channels if frankly sporadic emanations from the Atmos speakers, often again with regard to music but also occasionally offering ambient environmental effects in some of the outdoor moments in particular. Dialogue is rendered cleanly and clearly throughout. Optional English and Spanish subtitles are available.

Knock Knock 4K Blu-ray Movie, Special Features and Extras 

• The Art of Seduction: Looking Back at Knock, Knock (UHD; 28:04) is a really fun retrospective with some great interviews and some nice overt mentions of Death Game that should make my long ago acquaintance at the choral concert very happy.


• Establishing Shot with Eli Roth (UHD; 3:36) is a nice little promotional feature for 4K masters, and, yes, that's kind of a joke.


• Theatrical Trailer (HD; 1:47)


• Photo Gallery (HD; 1:39)


• Legacy Special Features

Audio Commentary with Eli Roth, Lorenzo Izzo, Nicolas Lopez and Colleen Camp




Deleted Scenes (HD; 4:51) feature optional commentary by Eli Roth.




The Art of Destruction: The Making of Knock Knock (HD; 14:42) is a standard issue EPK with some decent interviews, especially with Roth, who discusses having discovered Death Game back in the day and having loved it.

The DigiPack features an illustration of Evan as a hostage tied to a chair on the front, with the girls at the door in the rain on the back. The inner panels offer a kind of mid-century ad illustration depiction of partying going on in the house, shown from an outsider's perspective. The DigiPack is enclosed in a thin slipcover which has a hinged cover itself. The outside has the title with stars, with the back repeating the imagery of the girls in the rain. Opening the slipcover's hinged cover offers a peekaboo view of the girls through the viewing hole on the front door and an image of Evan with a remote.

A digital copy is also included.

Knock Knock 4K Blu-ray Movie, Overall Score and Recommendation 

This film will forever live in my memory for reasons maybe thankfully completely divorced from the actual movie. For those with actual memories of the film interested in picking up a copy, this new 4K UHD version has improved the odd artifacts seen on the 1080 version, but can't really get away from what looks like a kind of artificial digital capture. Technical merits are generally solid and the newly produced supplement is a lot of fun, with the somewhat unusual packaging offering another point of interest for collectors, for anyone who may be considering making a purchase.