Despite it was filmed earlier then Book of the Senseless (2015) it was mostly hidden until the very point of release of the latter, which has a link of the video ("?v=wwxEue_OKUI") written in a book itself, on the endpaper in post-credits scene.
Mykola Yeriomin: [multilinguality] Book of the Senseless has passages in English, Russian and Latin. Also, Russian language is heard in distorted dialogues.
Mykola Yeriomin: [Sudden Actors] Mikhail Bondarev (seen in a post-credits scene), Yaroslav Kozak (heard in the post-credits scene) and Leonid Syplyi (heard in a post-credits scene, credited as Leonid Sipliy).
Mykola Yeriomin: [Askold Tutylopydirskiy] his name is ciphered/hidden on Page 2 (if you don't count the endpapers).
Mykola Yeriomin: [Communal Universes] If you don't count the endpapers certain characters and events are referenced: Part 1 - Mountain Mosquito (described and drawn) from Twenty Years of Boredom (2013), G.G. Zaporoshets (referenced) and Surgeon ("battle syringes") from Noch' Naprolyot (2011), Under Construction (2015), Split Second (first appearing in The Born Defecation (2012), taking a huge part in Vedro (2013) and Komunalne; drawn and described); Page 2 - Voice of the Beginning from Twenty Years of Boredom (2013) and S iralnaya mashina (2007) are referenced; Page 5 - Gruppa MV-A10 (2013) is referenced; Page 6 - The Man With The Saw from The Summer Is Close (2010) is referenced; Page 8 - Events of The Nose (2012) and Attack of the Banana Peel (2012) are alluded to.