WARNING: SPOILERS AHEAD!
Fridge Logic
Fridge Brilliance
- Throughout the game (most notably in the beginning), you're asked a few questions about motivation and if the rat on the operating table should die for the greater good. You're also given the chance to write your name, but Mad Rat already has a set name. Turns out, the name isn't given to Mad Rat, but rather to the scientist, and should you spare or kill the scientist, you'll see in his journal that his words indicate that you are the scientist.
- Rat God explains that many creatures are able to rewind time. Heart, after the credits, rewinds time. Heart is a cat. Cats, thus, can rewind time. You know that saying about cats having nine lives?
- Though rats are already quite agile, they're not known for jumping. Heart is actually from a cat, which are known for jumping. While the transplant ultimately fails, Heart does still possibly give Mad Rat some of his platforming prowess!
- Why is Rat God given a chibi anime-style design compared to the rest of the characters? Even the little human girl, the only other female character in the game, has simple almond-shaped eyes with large black dots for the irises, so why only Rat God? Take a look at her true parasite form, a cluster of egg-shaped cells with white nuclei that come in red and yellow colors. What on Rat God has similar colors and shapes? Her Big Anime Eyes.
- The Rat God has a very bright color palette in comparison to the rest of the characters. The Nightmares are also colored brightly, alluding to the fact that they're on her side.
- The song of the final stage is called 'Heartless Being', which very obviously refers to Rat God. While it's likely meant to refer to how cruel, manipulative, and selfish she is in her desperate attempts to have Mad Rat get eaten by a cat, she's also literally heartless. She's very heavily implied to be Toxoplasma gondii—as in, just cells with no heart to speak of!
- Phantom Moon's battle theme is "Mimolette." It's a peppy, upbeat song, and if you didn't know what Mimolette is, it's a lovely-sounding name—except Mimolette is France's most infamous cheese due to having been tunneled through with tiny spider-like creatures to give it its characteristic texture. It fits the Phantom Moon's nature as a brightly-colored being that's thoroughly unpleasant. In addition, Mimolette is spherical and bright yellow, just like Phantom Moon.
- In addition, the only Foreshadowing for the Phantom Moon is Mad Rat pointing out an unusual looking full moon right before Stage 3-2. He sees it during the daytime, during which a full moon is not possible (at least at non-polar latitudes), hinting that there is something suspicious about it.
- The final battle with the Rat God Virus is absolutely discordant and insane thanks to the massively off-beat music, but throughout the entire song you also have one aid: a steady, consistent beat. Mad Rat is fighting the absolute breakdown of the virus within his brain at the same time that Heart is, quite literally, giving him a beat to hang onto. Even better, the more optimistic and epic parts of the "Mad Rat, Die" theme draw directly from the "MAD RAT, ALIVE?" theme that introduced you to the game with a leitmotif, meaning the influence of the Heart that was the turning point of the plot is also the one thing that can undo this whole mess.
- Rat God's being nicer in the epilogue makes a lot of sense considering that Toxoplasma gondii usually doesn't negatively affect cats, causing diarrhea at worst. When she was transferred into Mad Rat via Heart, her survival instinct kicked in and had to find a way into another cat before she perished with Mad Rat. As for why she tried to prevent Mad Rat from rewinding time to before the transplant, she had no idea she came from a cat or even if she came from Heart at all. For all she knew, Mad Rat got infected by her at some point like the Stray Rats and even if she knew she came from Heart, she had no idea where Heart came from. Only Heart knew he came from a cat. So now that she's back in a cat, she's no longer living on her survival instinct and is able to relax and allow the player to relive Mad Rat and Heart's adventure.
- Everything moves on beat with the music, which is the game's main gimmick. The main character is a rat. What's that trope about moving on beat with the music, again?
Fridge Horror
- Mad Rat believes that the scientist put the Rat God into him during the heart transplant. However, the only thing the scientist placed within Mad Rat was Heart, who is the Heart of a cat. So the Rat God got what she wanted.
- The Doctor's intentions behind the transplant, particularly the one based on the benign choices made at the beginning of the game. Was the Doctor doing a cross-species transplant as part of an experiment for the sake of the improvement of medicine? Was it all for humankind or even other animals and Mad Rat was just unlucky enough to be chosen? And even if the Doctor did it purely to save Mad Rat's life, the fact that they were willing to sacrifice a cat and transplant its heart into a rat, two completely incompatible animals, calls into question their medical expertise and sanity.
