In Jet Set Willy: Online, players navigate a sprawling mansion filled with various rooms and challenges, collecting items and avoiding obstacles. The core mechanics involve platforming skills, puzzle-solving, and resource management as players strive to complete their objectives.

The storyline of Jet Set Willy: Online follows the titular character, Willy, who must clean up his mansion after a wild party, collecting items and avoiding the ghosts of his past. Players explore the mansion's many rooms, each filled with unique challenges and secrets.

Jet Set Willy: Online stands out with its vibrant pixel art style and the ability to play cooperatively with friends or compete against others in real-time, enhancing the nostalgic experience with modern multiplayer dynamics.