"The Thunder Force series (サンダーフォース, Sandāfōsu, also Thunderforce) is a series of scrolling shooter type video games developed by the Japanese software company Technosoft. The games are known by fans of the genre for their hardcore appeal, pleasing graphics, and generally well composed synthesizer-based soundtracks.
The series' first game appeared a variety of Japanese computers, such as the Sharp X1 and the NEC PC-8801 mkII. The majority of installments in the series appeared on the Mega Drive console, where the series gained much of its popularity. The most recent entry was released on PlayStation2."
Source: Wikipedia, "Thunder_Force_(series)", available under the CC-BY-SA License.