According to the dates given in the manuals, this game takes place after Wizards & Warriors III, although it was published earlier. Malkil is back at his evil deeds. He has abducted Princess Elaine and taken her to his Fortress of Fear. It's up to Kuros to save her.
This is a tool-assisted speedrun, made on an emulator, using frame-by-frame shooting, savestates, and rerecords to overcome reaction time and human error. As such, it is purely a form of entertainment, and is not designed to show skill.