Underfell Sans Fight

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Underfell Sans Fight | Bad Time Simulator Pacifist Boss Edition

Released:September 11, 2025

Alternate universe

🎮 Controls: Arrow keys to move, hold up arrow to jump (blue soul), Z to select/forward text, X to deselect

🕊️ Pacifist Boss: Remember, sparing is necessary for the real ending in Underfell

💡 Tip: For best performance, avoid fullscreen mode as it may cause lag and pixel distortion

👨‍💻 Developer: loganvcairns (Scratch)

Underfell Sans Fight - Pacifist boss Bad Time Simulator battle

Tired of the lazy, joking Sans from the original Undertale? Prepare for a completely different challenge! This Bad Time Simulator variant takes you into a twisted underground world where all characters are darker and more ruthless. Face the most brutal and challenging Sans ever created in this intense Undertale fan game.

Pacifist Boss Battle System

This Bad Time Simulator Underfell edition features a completely transformed Sans battle experience. Players face a ruthless, malicious version of Sans with redesigned attack patterns and a dark, oppressive atmosphere that will test even the most skilled players.

Character Transformation

In this world, Sans is no longer your friend but your most terrifying enemy:

•Malicious and mocking dialogue that creates constant pressure
•Ruthless and deadly attacks designed to overwhelm players
•Complete personality reversal from the original Undertale
•Strategic sparing system that affects battle outcomes

This transformation creates an entirely different battle experience that challenges both skill and emotional resilience.

Enhanced Visual and Audio Experience

The game features comprehensive upgrades in visual and audio design:

•Dark, oppressive color scheme that creates an atmosphere of despair
•Redesigned, more complex bullet patterns that test reaction speed
•Aggressive background music that amplifies the brutal atmosphere
•Visual and audio elements that perfectly capture Underfell's cruel world

Every melody and attack is filled with despair and anger, creating an immersive dark experience.

Underfell Sans Fight gameplay - Pacifist boss Bad Time Simulator battle

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Underfell Sans Fight

Underfell Sans Fight | Bad Time Simulator Pacifist Boss Edition

Game Overview

Pacifist Boss Battle System

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