Warning: This post contains major SPOILERS for Ghostbusters: Afterlife.
It's fair to say that returning characters from Ghostbusters, but also secret cameos alongside the new generation of characters. It is, in other words, the right blend of fan-service and legacy intrigue.
Strangely castigated for that fan-service, Ghostbusters: Afterlife has picked up divided reviews, initially ranking it lower than Ghostbusters (2016), but that cynicism is myopic. The Paul Feig reboot failed because it didn't pay reverence to the original, and lambasting a direct sequel for doing exactly what fans of the franchise wanted in the first place is not to be celebrated. It shows an inherent misunderstanding of what this franchise is. And crucially, Ghostbusters: Afterlife limits the appearances by the original Ghostbusters to a few minutes in total, while also setting up a future where more Ghostbusters movies - with a new team - is possible.
The mixed Ghostbusters: Afterlife reviews aside, the movie is a treat for fans of the franchise, packing in subtle and overt nods to the original movie and the wider lore of the Ghostbusters universe. Here's every Easter egg, reference, and homage in Ghostbusters: Afterlife.
23. Ivo Shandor Mining Company (And Summerville History)
The whole premise of Ghostbusters: Afterlife is based on the idea that notorious Gozer follower and cultist Ivo Shandor - the architect of the building in Ghostbusters (1984) that was secretly a PKE antenna to help Gozer break through - used Summerville as the source of the building's metals. Quite why that was necessary when Shandor's own tomb was on the site of a literal hellmouth is a little odd, but as a result, Summerville was all built by Shandor and his name is on lots of buildings, including the mining company. As another Shandor reference, foreshadowing the character's reappearance, when Phoebe looks up the Ghostbusters commercial, the recommended videos to the side include one about Shandorian cultists. Shandor himself is played by JK Simmons in a secret (but not uncredited) cameo appearance that lasts all of a few seconds.
22. Egon (And Ray's) Revelation 6: 12 Scripture Callback
As revealed by the trailer, Ray Stantz has biblical scripture tattooed on his arm, and the same scripture - Revelations 6:12 - is used by Egon as a warning on the entrance to the "dirt farm". The scripture also appeared in Ghostbusters as Winston and Ray pondered the portents of the apocalypse:
Ray: And I looked, as he opened the Sixth Seal and behold there was a great earthquake, and the sun became as black as sackcloth and the moon became as blood.
Winston: And the seas boiled and skies fell.
The expansion of that quote into 6:12 includes the line about the sky turning black and the moon turning red.
21. The Zuul Statue On Egon's Desk
When Phoebe first explores Egon's house, she discovers a small stone statue of Zuul on his desk. Obviously, on a far more significant scale, the statue under Summerville's mountain depicts also Gozer the Destructer and her minions, Zuul and Vinz Clortho (the Gatekeeper and the Keymaster). Gozer's return confirms the backstory from Ghostbusters that suggested The Traveler had been to Earth before, expanding on it more specifically to tie the entity to several major catastrophes on Earth. In a surprise, Gozer is played (at least in "human" form) by Olivia Wilde.
20. Egon's Asymetrical Book-Stacking (And The Big Hint)
The opening act of Ghostbusters: Afterlife has a big hint at Egon's ghostly presence in his farmhouse. When Phoebe, Trevor, and Callie move in, they see a pile of books in the living room. They're stacked precariously high and are clearly a nod back to the ones the Ghostbusters found in their hunt for the New York Public Library ghost in 1984. “Asymmetrical book stacking!” as Ray calls it is a known sign of poltergeist activity.
19. Janine Loves Egon (Or Does She?)
In a strange quirk, Afterlife doesn't seem to follow the canon of Ghostbusters II explicitly when it comes to Janine (Annie Potts) and Egon's relationship. She calls herself Egon's friend, with a loaded emphasis revealing their relationship had greater depths. In Ghostbusters II, Egon and Janine have split up after the original movie brought them together, with the latter in a relationship with Rick Moranis' Louis that isn't mentioned here. Louis sitting the movie out makes that somewhat logical, but it feels like the canon explanation for their relationship draws more from Extreme Ghostbusters, that saw them locked in a will0they-wont-they dynamic that ultimately saw Egon's job and ghosts get in the way.
18. Egon Still Collects "Spores, Molds, And Fungus"
As well as lots of the old Ghostbusters equipment - which obviously includes Egon's PKE Meter and the first original proton pack that Phoebe finds - his secret underground lab also has jars of mushrooms and lots of labeled Petri dishes. This is a nod back to Egon's now-legendary awkward "chat-up" line to Janine from the original Ghostbusters: "I collect spores, molds, and fungus.”
17. Egon's Chess Set Is A Touching Call-Back
Egon's choice to communicate with Phoebe through the chess set is an interesting one in two respects: first, an issue of the Ghostbusters' IDW comics run saw Death challenge Egon to a game of chess to save his mortal soul (Egon's stand-din, Eduardo, wins). More touchingly, The Real Ghostbusters confirms that Egon loves chess but has no-one to play with: him connecting with his isolated granddaughter through a shared appreciation of the game is a clever deep cut.
16. The 3 Horror Movies Mentioned In Ghostbusters: Afterlife (Including An Ivan Reitman Deep Cut)
There are three horror movies shown or mentioned in Ghostbusters: Afterlife. The first two are shown by Mr Grooberson to his class - Stephen King's Kujo, and then Child's Play. The third is a more personal reference. On Summerville's cinema marquee is Cannibal Girls, which was Ivan Reitman's second directorial feature in 1973, a decade before he took on Ghostbusters.
15. Tobin's Spirit Guide
The book Phoebe and Podcast consult to find out the lore of Gozer and the devil dogs is Tobin's Spirit Guide, which features heavily throughout Ghostbusters expanded lore, including the animated spin-off shows and The Video Game. It's also the same source that Ray Stantz consults when Venkman hears a possessed Dana say the name Gozer in Ghostbusters (1984). The same book also appears in Buffy The Vampire Slayer.
14. Egon's Crunch Bar
When Phoebe finds the Ghostbusters uniforms hidden in Egon's underground hidden basement, she looks in the top pocket of Egon's overalls and finds a Nestle Crunch bar. It's a deep cut reference back to Ghostbusters, immediately after the original team are kicked out of university and Venkman says to Egon, "You.... you've earned this" as he hands him a Nestle Crunch bar. It's never really explained in-universe, and was widely assumed to be product placement, but in the director's commentary for the first movie, Ivan Reitman claims that it was a conscious idea that Egon would be constantly snacking.
