Silkworm also spawned what many consider to be a spiritual successor to the game - SWIV.[citation needed] While SWIV 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. SWIV was described in the game's manual to mean both "Special Weapons Intercept Vehicles" and "Silkworm IV".
