requires that the player have two satellite ships. Development Thunder Force IV was developed in Japan by Technosoft as the third Thunder Force game for the Mega Drive. Only the sound department was brought over from the original staff of Thunder Force II (1988) and Thunder Force III (1990); the rest of the team had previously ported the pinball game Devil's Crush to the Mega Drive. They chose to develop Thunder Force IV when given the opportunity to develop an original game. Having taken the reins for the Thunder Force series, the team felt a responsibility to surpass the quality of earlier series titles. They borrowed code from the previous games, and built upon it using what they learned when porting Devil's Crush. The composer for Thunder Force IV previously worked on Thunder Force III and also composed some original music for Devil's Crush. The sound team staff, led by Naosuke Arai, were fans of heavy metal, so they worked on finding a method to create an electric guitar sound using the Mega Drive's FM synthesizer. They ran into difficulties and eventually settled on using the system's distortion sound effects to positive results. Release Technosoft held a promotional event for the game at a convention in Tokyo on June 7, 1992. The event included a tournament, giving fans an early opportunity to play the game. The game was released in Japan on July 24, and in Europe and North America in January 1993. Sega of America renamed the North American version to . The game was ported to the Sega Saturn as a part of Thunder Force: Gold Pack 2, a compilation disc released on November 29, 1996, in Japan. The compilation also includes Thunder Force AC (an arcade port of Thunder Force III). This version improved on the original by eliminating sluggish frame rate issues, adding an easier mode which gives the player bonus defensive abilities, as well as adding the fighter from Thunder Force III as a secret playable ship. In 2016, Sega acquired the rights to the Thunder Force series. Two years later, the game was released on September 20, 2018, along with Sonic the Hedgehog (1991) on Nintendo Switch and other Sega games under the Sega Ages brand. Players can choose between the Japanese and international versions and take advantage of the improvements and other features from the Saturn port. Reception Thunder Force IV was quickly