Silkworm is a horizontally scrolling shooter developed by Tecmo and first released for arcades in 1988. In 1989, it was ported to the Amiga, Atari ST, Commodore 64, ZX Spectrum, Amstrad CPC and NES (1990) systems by The Sales Curve and released by Virgin Mastertronic.
Silkworm inspired the game SWIV and even though it was not a direct sequel, it followed the same core gameplay design of a helicopter/jeep team, albeit as a vertically scrolling shooter instead of a horizontally scrolling one and was described as "inspired by" and a spiritual successor by several reviews, both of the time and contemporary, respectively.