Get ready for a brutal challenge in Bad Time Simulator, a fan-made bullet hell game that puts your reflexes to the ultimate test. Inspired by the legendary Undertale boss fight with Sans from the Genocide route, this game recreates one of the most intense encounters in indie game history—down to every bone, blast, and blink.
You control a red heart—the embodiment of your soul—confined within a small moving box. Your mission? Survive a non-stop barrage of Sans’ signature attacks. From bone barrages to Gaster Blaster beams, every wave is designed to punish hesitation and reward perfect timing.
The game strips out the narrative to focus purely on survival and reaction, challenging players with precise hitboxes and rapid patterns. Two main modes offer varied play: