Tear Jerker / Mad Rat Dead

• Mad Rat tries to warn his fellow rats about the scientist who might kill them, but his fellow rats refuse to listen, preferring to die by a human scientist instead of dying by the dangers outside. Mad Rat's prediction ended up coming true: his fellow rats got turned into zombies due to cerebral experimentation. Trapped there, Mad Rat is forced to fight them. Heart and the Rat God are remorseful that Mad Rat had killed his former friends, whereas Mad Rat, even if he denies being emotionally hurt by the process, is still haunted (literally) by their ghosts.
• Despite Heart's support of Mad Rat's mission while trying to get him to see better alternatives to his mission, Mad Rat is frequently dismissive of Heart. This goes to a head where Mad Rat wants some cheese that Heart is denying him. The two end up bickering so much, they end up in a fight... literally. Once Mad Rat wins the boss battle, he gloats at Heart. Heart had to literally slap some sense into him before he can see that he was under a hallucination.
• Mad Rat finds some outside rats hallucinating that they are getting lots of cheese. Mad Rat tries to warn them, but a cat immediately kills them. Mad Rat then becomes regretful at not being able to rescue them.
• Mad Rat would have died to the same cat, had not a girl picked up Mad Rat in time. Later, they find out that she had died in a car crash. This spurs the normally cynical Mad Rat to rewind time and keep her from dying.
• Depending on your answers in the beginning of the game, the scientist may have good reasons behind doing the experiment with Mad Rat and even expressing regret with his actions. The scientist might even outright say that Mad Rat should live. Even farther into the game, the game reveals that the 'experiment' was actually a heart transplant… that failed. Despite all of this, the scientist can die by the hand of the same rat that the scientist wanted to live, overriding Heart's protests of that matter.
• Once Mad Rat deals with the scientist (either through mercy or murder), Heart and Mad Rat go to terms with their death meaning that they would no longer be able to be together.
• Do you remember how the Rat God is helping Mad Rat with his revenge? Unfortunately, this was all a trap: the Rat God was not only pretending to help Mad Rat, but also causing hallucinations because she wanted a cat to eat Mad Rat. Worse, the Rat God uses her time powers in rewinding Mad Rat back to before his vivisection, clearly knowing that she is not only separating Mad Rat from Heart and preventing him from living his life his way, but also dooming the outside rats and the girl to their fates. Worse still, Mad Rat was not really being vivisected, but rather undergoing a heart transplant… which failed. In other words, even if he does defeat the Rat God, he is still going to die before the day is over.
• Before and after Mad Rat defeats the Rat God (which was actually a parasite), Mad Rat insists on preventing the transplant, despite knowing that he would die. He just does not want Heart to die, too. Mad Rat keeps overriding Heart's protests all the while.
• Sure, The Rat God may have constantly lied, exploited, psychologically tortured, and wanted to kill Mad Rat, but the only way she, who is actually a parasite, could reproduce, was having a cat eat Mad Rat.
• When Mad Rat goes back to before the transplant, he manages to leave his cage… but, because of his bad heart, he is having a very hard time walking. Despite this, he frees Heart and insists that he leave free without him because he does not want to have Heart see him die.
• Heart himself is actually a cat. He hid that information because Mad Rat's instinctive hatred of cats risked overriding the friendship he had with him. Thankfully, Mad Rat does not care.
• At the end of it all, Mad Rat is doomed no matter what happens. If he succumbs to the Rat God's hallucinations, then he'll simply be eaten. If he defeats the Rat God to avert this, freeing himself from her influence won't win him much more time, since he still has a weak heart even after the transplant. And even if the events of the game had never happened, he was going to die of heart failure by the end of the day anyway. At the very least, taking the final option in the end allows him to save some lives and leave his mark on the world like he wanted, but even so, everything Mad Rat went through boils down to simply accepting his impending death and choosing the best way to spend his final day before he's gone.

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