The Cat Lady
Susan Ashworth's favorite coffee mug is blue, which stands out in contrast to the rest of the environment. The cup's color is a nod to the engine the game was built on, AGS, which has a blue cup as it's mascot.
After being caught by Joe Davis in his apartment, the player can choose Susan to say that she's a gas inspector and was inspecting his apartment for a gas leak. This is a reference to one of the puzzles in Downfall, where the player has to deliberately cause a stove to leak gas so that when a character lights a cigarette in the room it's located in it'll cause an explosion. It should be noted that this was originally intended as a reference to the original Downfall.
While Susan and Mitzi Hunt are creating a map of the Helen Road flat, Susan states that Joe and Ivy live across the hall, but then quickly comments she thinks Ivy's name is actually Sophie. This is a reference to the antagonist of the same name in Downfall: Redux, who represents a mirrored version of Ivy. It should be noted that this was originally intended as a reference to the original Downfall.
I Have No Mouth, and I Must Scream
In the garden of Quiet Haven Hotel, a message can be seen inscribed on one of the pillars of the garden fence, which cannot be interacted with. This message looks similar to AM's "Message of Hate" seen inscribed on a giant, monolithic pillar in the intro of the adventure game I Have No Mouth, and I Must Scream.
In the "Lucky Dip" option on the extras menu, it's possible to find some concept art for the original 2009 Downfall - A Horror Adventure Game. Finding this will earn the player an achievement.
The Slenderman can make a surprise appearance when you're playing as Agnes in the forest, if you go back after entering a building similar to the one from the famous free indie horror game Slender: The Eight Pages. Remigiusz Michalski has shown a fascination for the game and The Slenderman mythos before, with The Slenderman also having an appearance at the end of the the anniversary trailer for The Cat Lady. The player is awarded an achievement for this.
Noises She Makes In Their Bed
Joe plays the song used for the main theme of The Cat Lady on a piano on the fourth floor of Quiet Haven Hotel. This reference also works in the fact that the person who wrote and played the song, Jesse "Warmer" Gunn, is the voice actor of Joe, being a fan of Remigiusz Michalski's games since Downfall - A Horror Adventure Game. Another reference also appears in the same scene, with Agnes saying the song sounds like Coldplay, which also serves as a callback to a line in The Cat Lady. An achievement named after the song is awarded to the player for this.
When Agnes wakes up in a random hotel room, she can turn on the radio. Doing so will play a song by Jesse "Warmer" Gunn, one of the outsourced musicians for the game. The name of the achievement for doing so is a reference to the band Radiohead, with the image for the achievement appropriately being Agnes with a radio for a head.
If Agnes lies that she'll drink the soup, The Queen of Maggots will say her true name is Lorelai, of course a reference to the third and last game in the trilogy Lorelai. An achievement is awarded for doing this, the image of which is the eponymous protagonist of Lorelai, in reference to the fact that The Queen of Maggots and her share the same name.
Just Do It
Choosing certain dialogue options when talking with Dr. Frank Zellman near the end of the game will cause him to reference the famous 2015 Shia LaBeouf meme "Just Do It." This is referenced further in the image for the achievement, being Joe doing the Shia LaBeouf pose in front of a green screen.
|You found some concept art in the lucky dip!|
|No Eyes, Always Watching|
|You spotted Slenderman in the forest!|
|Noises She Makes In Their Bed|
|Joe plays a tune on the piano.|
|Agnes turned on the radio.|
|You persuaded the Queen of Maggots to say her name.|
|Just Do It|
|You were given a motivational speech.|