This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Disney's Villains' Revenge
The Snow White level. You have a limited amount of time, and you have to go through a book full of recipes and spells and sorting through ingredients in a dimly lit dungeon while Snow White is fading away. It's a pretty stressful experience for a little kid.
You can also mess up the potion and cause Prince Charming (as in, Cinderella's Prince Charming) to arrive instead of Snow White's prince. He finds that the slipper is too big for her foot, and leaves.
Also, whenever your time is up, the Queen suddenly comes back, takes a potion, turns into the hag, and goes back down to put one of the seven dwarfs to sleep. What makes it worse is that nothing indicates when she is coming back, and if you don't have a watch near you, she'll scare you every time she comes.
The prelude to the final battle has the player's bedroom ceiling cracking open and the walls dissolving around them, to reveal each villain has stolen the happy ending—and they're about to attack you.
When you defeat each villain, there's a wacky little animated sequence of their defeat. Except for Queen Grimhilde. After she gets hit with her magical ammunition, she transforms into an old hag. She then looks at her reflection in the Magic Mirror, which shatters because of her appearance, so she screams at the top of her lungs with bulging eyes.
If you follow the white rabbit in the Alice in Wonderland level before grabbing Alice's head you're treated to a cutscene where the rabbit goes through a tiny door and escape the Queen of Hearts' maze. But you don't. You're stopped by guards and the Queen herself who proceeds to walk up to the camera until her face is literally inches away from it and screams her iconic "Off With Their Heads" line as her mouth engulfs the camera and it all fades to black. Safe to say this player got the message and never tried that again.
The fact that Alice actually got beheaded this time! The good news is that she's still alive and can still get her head back on, apparently because Wonderland is just that weird.
The entire level is creepy as heck. While looking for Alice's head, you have to listen out for her voice and figure out which part of the hedge maze to go through based on where her voice sounds the loudest. All the while you see the White Rabbit running by shouting about how late he is and you hear other strange voices trying to mess you up. To top it all off, obstacles appear in your way as you race through the maze that you have to click on to get rid of, the worst being a big, scary computer animated Cheshire Cat head that opens his mouth wide as if to eat you. Jiminy Cricket's urgent tone of voice while shouting "Stop that Cheshire Cat!" doesn't help.
Each of the altered Disney stories have had their worlds altered in some way. Wonderland and Neverland remain the same, but Dumbo's circus is now a huge clown-shaped Circus of Fear where poor Dumbo is continuously abused and humiliated since he can't fly. As for Snow White's world, Queen Grimhilde has swapped the dwarves' lovely cottage for a creepy apple-shaped fortress and all of the trees are actually alive and evil rather than just from Snow White's imagination.