Chapter 11:
-According to Gary Carlston, who first proposed the idea for the Carmen Santiego games, Carmen's maiden name was actually Sondberg, and she's Swedish. It was just a tongue-in-cheek reply to people who claimed that the game associated a Hispanic surname with criminality, but this trivia is actually very useful as an alternative to straight-up namedrops.
Chapter 14:
-Much like a certain pair of kids and their aunt in Chapter 13, "Primo" is the expy and human version of a game character. His tale about how he was robbed and stuffed into the trunk of his car on PC Continent? That's referencing a real event that happened to an Italian dev, while he was working on the Beyond Good and Evil PC port in France.
Chapter 15:
-Mr. Esaka's whole detective persona is a homage to a certain old SNK mascot, G-Mantle. His first name, Shinkyo, is a fusion of "Shin Nihon Kikaku" and "Kyo", while his pitbull, Lord Okada, is named after Chad Okada, "The Game Lord", a famous employee in the marketing department of SNK America during the early 90s. Neo Geo's pitbull mascot also came into existence around the same time.
-The whole thing about little C-Sha drawing posters of her beating up young Shinkyo? That's referencing a poster drawn by Street Fighter II's co-designer, in which Sagat's defeated opponent has Robert's hairstyle and Ryo's karate gi (said character was later officialized as Dan Hibiki's father, and Dan himself is also a joke character, created to poke fun at SNK).
Chapter 16:
-Verdna's amulet...guess which company is also a pioneer of the CRPG genre, alongside Wizardry? Whose games served as an inspiration for Dragon Quest's overhead perspective, and use the Ankh symbol to represent its player character? Hint: You've seen its name in the first Reference Galore.
-Atless, the masked vigilante who works as an Intel Agent for Planeptune, is based on Atlus. Her friendship with Verdna is mostly referencing Etrian Odyssey, which could be described as a "Wizardry-like" first-person dungeon crawl game that inherits many of Wizardry's classic mechanics, such as mapping out dungeons on your own.
-The Guild's app mascot, Sir Airuu, is basically a Felyne, and Felynes are called "Airuu" in Japanese.
Chapter 17:
-Shauni the wildlife photographer, Hubert H. and Uncle P...Yeah, all of them are expies of game characters. The entire wildlife photography app is mirroring how Jade earns money in Beyond Good and Evil.
Chapter 18:
-"From-From" is, of course, the From Software Maker. Bandai Namco published the Dark Souls trilogy, but their relationship began back in the Armored Core days, and their collab project, Another Century's Episode, is basically "Super Robot Wars, but Armored Core".
Chapter 19:
-Since the Chuck E. Cheese mascot is a rodent...all of their employees are rats in their Neptunia incarnation.
Chapter 21:
-Brøø's mention that she'd learned karate in Lowee is referencing Brøderbund's Karateka game, which became a hit when ported to the NES. Her nicknames for the shadow people, "Grues" and "Bungelings", come from Infocom's Zork text adventure games and the Bungeling Empire, a frequent villain in early Brøderbund games.
-The book colors are referencing a certain bestselling adventure game in the early 90s, published by Brøderbund on the Apple Mac. That's all I'm gonna say.
-The entire memory sequence is based on the Adventure game for Atari 2600, an adaptation of Colossal Cave Adventure—a text adventure game on mainframe computers. It's also one of the first games to feature an "Easter Egg", in the form of a single pixel item that can unlock a secret room, which has the developer's name in it.
-The disembodied voice, "Pamola", came from Atari 5200's codename in development, "Pam". The 5200, because of its outdated hardware, lack of backwards compatibility, crappy controller design, and, most importantly, its release right before the Crash of '83, was discontinued after just two years on the market.
Chapter 22:
-The first part of "Tendo Uemura" is pretty obvious, but the surname in Rubis's alias is a reference to Masayuki Uemura, designer of the Famicom and leader of Nintendo's R&D 2 Department.
Chapter 23:
-Rubis casts her spells with metal cards, which is, unsurprisingly, a reference to Nintendo's hanafuda cards production business. Her spell names are based on real hanafuda cards, too.
Chapter 24:
-Hyperdimension's Panason is known for its adult materials. In Japan, a lot of cheap porn games had been released on the 3DO, due to its low licensing fee and lax regulation. The "Self-appointed Photographic Genius Guy" Dameko mentioned is a homage to Earthbound's Camera Man.
Chapter 27:
-Everything that appears in Dameko's secret base references some kind of Nintendo accessories.
Chapter 30:
-Poor Maxy Simms. Maxis, technically, still exists as a studio. It's just the main Emeryville studio that's shut down. Brøderbund is the publisher of the first SimCity game, even though they originally rejected the idea when Will Wright came to them (since simulation games with no way to "win" weren't a thing yet).
-Also, there was a merger talk between Brøderbund and EA in the early 90s. It didn't work out because Myst sold too well, which caused Brøderbund's stock to skyrocket, and the new, much higher price meant it's no longer financially wise for EA to purchase the company.
Chapter 31:
-Viven's full name, Viven d'Eau, references Vivendi's origin as Compagnie Generale des Eaux, a water company created under the decree of Napoleon III.
-Vivendi also owned Blizzard since 1998, until the Activision-Blizzard merger in 2008, after which the joint company bought their independence from Vivendi in 2013. Hence, Viven's dislike for Aktivis and her "previous foster kid".
-EA Tiburon is the sub-studio that makes the Madden NFL games, and their old logo is a hammerhead shark, thus Tibu is a literal talking shark. Dice represents Digital Illusions CE, creator of the Battlefield franchise and Frostbite Engine.
-Personal headcanon: Makers who are known for their game engines—DICE and Frostbite, for example, are all holographic technology specialists.