Thunder Force IV is a side-scrolling shoot 'em up video game developed by Technosoft as the fourth installment of the Thunder Force series. It was released respectively in July and September 1992 for the Sega Mega Drive/Genesis console in Japan and the United States, and in December of the same year in Europe. In the USA, Sega of America decided to rename the game as Lightening Force: Quest for the Darkstar [sic]. In Europe the name was left as Thunder Force IV. Source: Wikipedia, "Lightening Force", available under the CC-BY-SA License.