Nightmare Fuel / Sonic.Exe: Spirits of Hell

In the first game:

Despite being a Sonic.exe fangame, Sonic.exe: Spirits of Hell does not have as much Nightmare Fuel as most of them. But there are some noteworthy times that are really unsettling.

• The game's title screen can be quite creepy, as below the 6 main characters is a glowing red circle placed in the middle of start button, paying close attention to it reveals that it's in fact Exeller's glowing red eyes staring directly at you and as well as tears of blood, which is the only part visible as the rest is completely covered in darkness. This contrasts with the sequel's title screen where it simply shows a city, and the main characters being together.
• The Exeller jumpscares, especially since the game is generally seldom on this. The fact that it happens is a sign that you've screwed up pretty badly.
  • In Tails' route where he comes across the trail of dead miniature animals, there are bloodied palm trees around, and one of them will have Exeller peeking out. If you jump on that tree, a jumpscare will occur accompanied by a message that says "You found me? Good job!"
  • In the same route where Tails tells to himself that he needs to go back to the Tornado and warn the others about the situation. If you do just that without a green ring in your hand, he will be chased by Exeller, and if he catches Tails, a jumpscare will happen and ends with a "There are no easter eggs!" message.
  • In Robotnik's opening Zone, after Exeller has broken through his base. Robotnik has 30 seconds to rendezvous with Scratch, Grounder, and Metal Sonic, and if you run out of time... the game proceeds as normal, until Robotnik decides to go near the exit where instead of going further, Exeller will suddenly appear in front of him and a jumpscare will initiate.
  • In Robotnik and Tails' route. If Robotnik chooses to open the vents to clear out a fog, Exeller will enter through the vent and suddenly lunge at him accompanied by a jumpscare. After this, Exeller will take Robotnik's place in the speaker and proceeds to kill Tails offscreen.
  • If the sole survivor decides not to obtain a black ring, Exeller will kill them before their respective final stage has started. If you wait at the character select screen that depicts a corrupted Tails, Knuckles, and Eggman, a jumpscare will occur.
• In Hide and Seek Act 1, multiple images of Sonic.exe (including, perhaps, Exetior and Exeller himself) flash in front of your eyes.
• During the Eggman and Tails duo run; you, as Tails have entered a facility that suddenly went dark and have to escape from Exeller who (as Eggman worriedly warns) is near him. It is set in a pitch black facility where the only area visible is a small circle around Tails and, as Eggman you have to constantly check the cameras to see if Exeller's in Tails' vicinity. If Exeller teleports to an area where Tails is... Now's the good time to run as fast as possible!
• If even one character dies in the route to the Golden Ending, it results in the two that manage to escape being killed.
  • If Tails dies, Eggman and Knuckles lament on how Tails sacrificed himself to save them only for Exeller to arrive to let them know it was a Senseless Sacrifice and kills them too.
  • If Eggman dies, Tails is aware that this means they will die too. Just as he says that, an undead Eggman arrives to tell them that he has no intention of working for Exeller alone before killing them.
  • Knuckles dying during his segment actually comes off slightly as a tearjerker as when he appears to kill Tails and Eggman, he expresses guilt over his failure and how he is being forced to kill them. If Knuckles is killed by Exeller when Tails approaches Sonic near the end though, he instead tells Tails how he is happy they aren't friends anymore and is disappointed he has to force them to join him.
  • After these scenes, Exeller speaks to the player directly how meaningless it is to save only one or two characters, all while challenging the player to try and save them all.
    Exeller: You still don't get it. Do you? Solo endings and duo endings serve no purpose. I'll just kill the stragglers offscreen. So, just try your luck and get the best ending. But don't think for a second I'll go easy on you.

In the sequel:

Compared to Spirits of Hell, Whisper of Soul contains more unsettling elements due to an expanded cast and routes.

• In Sally's route, she gets thrown in a nightmarish copy of Freedom City which Exeller watches over omniously.
• Cream's flashlight sequences, which are partly inspired from Five Nights at Freddy's 4 and The Joy of Creation.
  • In the first one that takes place inside Cream's house, if you get caught by an an evil looking Vanilla (Execun in disguise), you'll be treated to a jumpscare of her grabbing you (this is notable as the pre-release version did not contain said jumpscare).
  • The second one isn't better since it's set in the apartments of Freedom Tower where the lights went out and have to navigate the area with a flashlight to avoid the Execun clones. What's worse is that unlike Cream's house, these clones cannot be warded off with a flashlight and you have to avoid it lest you get assaulted by a split second jumpscare of Execun's red eyes and teeth. The only saving grace is that it is impossible to lose this stage as there are a limited amount of Execun clones you have to avoid (rather than actively hunt you down like Execun-Vanilla), and upon running into a large Execun clone you'll be thrown off immediately, and should you run fast, you'll automatically stop when you witness Execun killing Bunnie then lifting her corpse away.
• There also is a rather unsettling segment when you have to hide from Exeller's lackeys, Execun and Exebark (and at one point, from corrupted Amy and Tails).
• The clicking Quick Time Events, full stop. Partly because of the music, which makes both contexts horrible.
  • In Sally's route, she encounters fake Antoine (again, Execun in disguise) who not only turned off the lights rendering the area pitch black, but also disabled her only means of defending herself forcing Sally to hide from him, and you can also hear her breathing throughout the QTE. Worse.. Lose the QTE and, Sally will become so nervous that fake Antoine heard her and after 10 seconds have passed; there will be a jumpscare of him pouncing at you!^note This however pose some problems as while genuinely scary, his 3D model is of his post-reboot design instead of his pre-reboot appearance leading to a slight Nightmare Retardant
  • The occurrence in Tails' solo route is even worse, as it has Tails walking through darkness, with images of Amy, Sally, Cream, Knuckles, Robotnik and Tails himself covered in blood (and for some reason, Alice) flashing before him. This signifies just how close Tails is into crossing the Despair Event Horizon. Thankfully unlike the Sally version, there's no jumpscare this time around.
• The Prison Tower Zone. Shortly after evading Exebark, she has to leave the prison complex to reunite with Cream. What makes it scary is that the stage is dimly lit (not helped by a brief glimpse of shadowy creatures watching her every move), and worse of all, if you linger around without getting to a source of light or go into a patch of darkness, a 5 second timer will start and the Breathelessness theme will play and the stage gets darker as the timer counts down (which will accelerate it further if you touch the same dark patch). If the timer counts to 0, Amy will be devoured completely by darkness and she gets killed off-screen.^* Amy's icon will have her eyes filled completely with blood. Furthermore, the default continue screen which normally shows a character's soul will have a variation that reveal Amy's brutally maimed and mangled corpse with her soul standing over her dead body.
• If you ran out of lives during the boss fight against Execun in the True Ending route (or the QTE beforehand), you'll be treated to a most disturbing level in what is essentially a Call-Back to Nightmare Beginning's Suicide Hill but on a brutal and darker scale. To elaborate; it starts with a crying Cream witnessing her friends (including Robotnik) commit suicide one by one (in Sally's case, she allows a Chopper to bite her head off), then coming across multiple impaled heads of Tails Doll, and lastly... Seeing the sight of Vanilla, her mother hanged on a tree. Having succumbed to despair at that point (and partly because she felt that she failed her friends), Cream activates a speed Power-up to spindash her way through the spikes and kill herself.
• Tails and Cream's duo route has an unsettling ending. The two end up stuck in an elevator, and they have a heart to heart, going to sleep in a good mood... except when Tails wakes up, he learns, to his horror, that he has Gone Mad From The Isolation and begun to eat Cream.^* Pay attention to his fur color when he turns around and it shows that he's been cursed (presumably by Tails Doll) He tries to make the situation better for himself by turning the fact he was eating Cream into a Furry Reminder (Tails is a fox, Cream is a rabbit, and foxes eat rabbits), but that's not how Mobians work. Doubles as Nausea Fuel.

In the DLC:

There are also a few points of creepy content in the unfinished DLC for the saga.

• Early on in the game, if you grab a mysterious black ring multiple times in Green Hill Zone, the entire level crashes as everything literally goes haywire, with unnerving sounds to boot.
• The whole premise of the Majin Forest segment of the game, with the same level of creepiness as its source of inspiration. You know something's off if even Exeller hates the scenery.