Exitor

According to Christian A. Weber's blog, the developers started working on Exitor right after they got their first Amigas. It was supposed to be a vertically scrolling shoot 'em up inspired by Nichibutsu's 1985 arcade classic Terra Cresta (テラクレスタ). The player controls a flying craft to destroy the Mandler army before they destroy all of humanity. Exitor's background looks very much like Terra Cresta's background. As player you control a fighter plane that has to shoot down enemy vehicles and objects. Weber, Werner and Hugentobler never finished the game, though.

Source: https://stage.chludens.ch/games/exitor/