In the prologue, you can find a booklet from the furniture company IKEA on a worktable that shows the ship as a ready-to-assemble set made by IKEA.
In Sapienza, there is a plumber named Mario Salvatore in the sewers near the marina, wearing red. Beneath the mansion’s kitchen, there is another plumber fixing pipes named Luigi Salvatore, wearing green. These two are references to Mario and Luigi from the Mario series.
The “Daisy, Daisy” challenge in Hokkaido, where you use the robotic operating arms to assassinate Erich Soders, is a reference to HAL 9000 from 2001: A Space Odyssey.
If you roll Ayakashi all the way through the facility and outside, and then return to KAI, she will begin singing. Her song is another nod to HAL 9000.
In the second prologue mission, one of the possible aliases used by Jasper Knight is “Blind Tailor.” This is a nod to Hitman: Absolution’s character Tommy Clemenza, who was a blind tailor.
In the garage in Hokkaido, you can find a poster for Kane and Lynch, which was also developed by Io-Interactive.
If you shoot all 10 of the mini ninja toys in Hokkaido, the volcano will erupt.
When the Sapienza trailer came out, a Hitman fan misheard Agent 47’s line, “Check please” as “Jack Please,” and started a forum discussing about Jack. As a reference to this, the waiter in the final game is named Jack Please.
If you try to enter the mansion in Sapienza while wearing the plague doctor disguise, the guards will comment, “Looks like someone’s been playing too much Assassin’s Creed” and refuse to let you enter.
During the “World of Tomorrow” mission, if you use your sniper rifle to aim at the bells on a distant sailboat and hit each of the four bells in order from the lowest note to the highest note, a kraken will pull the boat under the water.
In Rocco’s apartment, the computer monitor displays a screenshot of Hitman: Sniper Challenge. Hitman: Sniper Challenge was a standalone Hitman game with an official competition, and Rocco is based on the competition’s winner.
Two targets in Paris, Harry “Smokey” Bagnato and Marv “Slick” Gonif, are references to Harry and Marv from Home Alone.
There is a catering van in Paris marked with the Mini Ninjas logo. Mini Ninjas is another game developed by Io-Interactive.
During the second prologue mission, you can find a few notes that mention Allan, which message like “God damn! We still need details here, Allan!” This is a reference to the meme that came from Hitman: Blood Money, where one of the item descriptions was “Allan please add details” instead of an actual description.
When of KAI’s lines while corrupted is “Oh, I hope there will be cake! There will be cake, won't there? I was promised, you see,” a reference to GLaDOS’s promises of cake in Portal.
The appearance of the AI Ayakashi might also be a reference to Wheatley from Portal 2.
In Colorado, you can come across two soldiers arguing over politics, specifically about the “billionaire presidential candidate” with a “famous hairdo.” This is most likely a reference Donald Trump.
In the previous episode, you could also overhear a hotel guest musing about becoming president to “make this country great again,” a reference to Trump’s campaign slogan.
If you shoot all 18 miniature gold elephant statues in Ken Morgan’s penthouse in Bangkok, the elephant statues at the front of the hotel will begin bleeding from their eyes.
In Hokkaido, the names on the high score board for the dancing game are the names of the Hitman Reddit moderators, Square Enix’s CEO, and other actual people. If you play the game while wearing the ninja disguise, you will earn first place under the name “Barcodeman_47.”