I really like how the game begins directly from the main menu and seamlessly transitions into the gameplay. It's a small detail, but it immediately creates a sense of immersion.
The moment you sit down, you're committed. There is no backing out, only the challenge of beating the monster at its own game.
Watching the cups shuffle while the creature never seems to lose focus on the candy creates a growing sense of dread. Each round makes the situation feel more hopeless, as though escape is impossible.
The panic starts to build the first time you realize how well he tracks the cup that contains the candy. Then comes the slow realization that every mistake has consequences. By the time the last of your fingers disappears, the tension has become almost unbearable.
This is a simple concept executed extremely well. The atmosphere, presentation, and psychological pressure work together to create a surprisingly memorable horror experience.