Gradius II: Gofer no Yabō, lit. "Gradius II: The Ambition of Gofer") is a horizontally-scrolling shooter originally released for the arcades in Japan in 1988. It is the sequel to original Gradius and was succeeded by Gradius III. Ports of Gradius II were released for the Family Computer, PC Engine, and X68000 in Japan. The original arcade version is also included in the Gradius Deluxe Pack compilation for the PlayStation and Sega Saturn and in Gradius Collection for the PlayStation Portable. The Famicom and PC Engine versions were re-released for the Wii Virtual Console in 2007.
No version of Gradius II was released in North America until its inclusion in the Gradius Collection in 2006. The Virtual Console re-release of the Famicom and PC Engine ports were released internationally as well. In Europe, Gradius II was released for the arcades under the title of Vulcan Venture.
Source: Wikipedia, "Gradius II", available under the CC-BY-SA License.