Nexus is a vertical reaction rhythm mobile game that combines mahjong elements with extreme hand-speed challenges. Sixteen sunset light orbs are arranged in a circle at the center of the screen. Each round randomly lights up one to three targets, and players must tap them accurately in the correct order within a limited time. Faster reactions earn higher scores, while three consecutive mistakes end the round. As the score increases, the number of lit targets grows and the time limit shortens, making the pace increasingly tense. The game supports pause, restart, and high-score recording. The rules are simple and easy to learn, yet it tests focus and strategic judgment.