Billing Displacement: The Stay-Puft Marshmallow Man is the most prominently featured character in the game, even displacing the Ghostbusters themselves.
Sequel Difficulty Drop: Aside from the artwork and sound differences, most of the changes from Haunted House to Ghostbusters Pinball were to make the game easier.
Because Sephiroth was practically raised in the Shinra building, the author reinterprets Scarlet, Heidegger, and Palmer as genuinely decent people who were like a large extended family to him, and that they would have undergone a Cynicism Catalyst if things in the story had happened according to canon. It helps that none of them have a canon backstory of how they came to be the way they were in the original game.
Scarlet in particular is depicted a formerTurk and an Honorary Aunt to Sephiroth. The story implies that the canonical events in Crisis Core and Before Crisis would have hardened her into the cold-hearted woman she is in the game.
Because we don't actually witness the murder of Genesis' parents on-screen, the author Retcons their deaths to being at the hands of one of their son's copies for being in the copy's way, and Genesis deeply regrets their demise after coming down from his degeneration-induced madness.
Nightmare Fuel: The Deepground chapters. Let's just say there's a reason the author provides a Trigger Warning at the beginning of those chapters and leave it at that...
When Sephiroth, Genesis, and the Tsviets are exposed to healing rain, the high quantity of Jenova cells in their bodies causes them to literally start melting away layer by layer.
The flashbacks and archived recordings of Hojo being a loving father to Sephiroth during the latter's childhood, knowing what he becomesby the timehissonisan adult.
It's also just as heartbreaking to watch Hojo slowly go insane as the Jenova cells he injected himself with feed on his doubts and insecurities about Sephiroth and Lucrecia.
When Vincent manages to dig up files pertaining to the experiment he was created for, Sephiroth pours over the video footage for hours in the desperate hope of hearing his mother's voice. He can't.
When the Restrictors discover the Tsviets' rule breaking, they kill Nero, removing his respirator and leaving him to die of suffocation slowly and most assuredly painfully.
When Sephiroth attempts to commit suicide in order to stop destroy Jenova, the J cells in their bodies allow him to have an astral conversation with his mother for the first time. It's equal parts sad and heartwarming at the same time.
Vincent's backstory is the same as in canon with a few twists.
Thanks to Chaos, Vincent survives almost dying due to Hojo's machinations more times than he can count
Vincent's angst stems more from PTSD due to his time in the lab rather a bad breakup
It takes several chapters before Vincent begins to work through the shock of being suddenly shoved twenty-five years into the future
Although Vincent and Lucrecia are still portrayed as being close, their relationship remains unrequited
The story manages to make Sephiroth even more of a woobie than he already was in Crisis Core. He:
Learns that everything Shinra told him all his life about his parents was a lie.
Found out that the reason they created him basically amounts to making more money.
Then he learns that his real mother almost died giving birth to him, forcing Hojo to put her in stasis.
Then, when he meets the first woman he's ever been attracted to, he finds out that she's dying, and that the only way to save her involves confronting his father.
Add all that together, and it's only thanks to Vincent that he didn't go off the deep end like he did in canon.
