Real-time mechanics are aspects of Undertale that use the computer's current date, time, or season to affect gameplay. These elements can range from aesthetic changes, such as the dating/friendship HUD, to game-changing aspects such as So Sorry's appearance.

Papyrus's Dating/Friendship HUD


Dating HUD during Papyrus's hangout with the protagonist.

During the date/hangout with Papyrus, the player can press C to open the Dating/Friendship HUD, which consists of a clock, a radar that tracks the Annoying Dog, a level of crime graph, a bar with "REEL IT IN!" above it, a population chart, and an egg.

The date shown on the clock matches the day on the player's computer, and the graphic next to it changes accordingly based on the time of day the player's computer provides.

River Person Dialogue

Tra la la. Somewhere, it's <Day of Week>.
So be careful.
— River Person

The River Person says this dialogue to the protagonist while the protagonist rides on their boat. The day of the week depends on what date it is on the player's computer.

Joystick Configuration Screen

Main article: Joystick Config

The joystick configuration theme changes depending on the season. The configuration determines the season by collecting the computer's location and date.

The theme of the configuration depends on the current season. The Annoying Dog wears relevant hats and has dialogue relevant to the current season.

Seasonal Quotes

  • Winter: "cold outside but stay warm inside of you"
  • Spring: "spring time - back to school"
  • Summer: "try to withstand the sun's life-giving rays"
  • Autumn: "sweep a leaf - sweep away a troubles"

So Sorry Boss Battle

So Sorry is a boss that the protagonist encounters if the computer's time and date are set to October 10th at 8 pm. Without this time and date, So Sorry does not appear in the Art Club Room. So Sorry can be fought at any time if the game is not connected to the Internet.

Gameplay Mechanics
Gameplay Mechanics Names • Encounter • SAVE - SAVE Point • Stats • GOLD • SOUL Modes • Bullet Board • Dimensional Box • Cell Phone (Toriel's Phone) • Serious Mode • Real Time Mechanics • Joystick Config • Trophies