Star Force

Star Force, (スターフォース) also released in arcades outside of Japan as Mega Force, is a vertical-scrolling shooter computer game released in 1984 by Tehkan.

Gameplay
In the game, the player pilots a starship called the Final Star, while shooting various enemies and destroying enemy structures for points.

Unlike later vertical scrolling shooters, like Toaplan's Twin Cobra, the Final Star had only two levels of weapon power and no secondary weapons like missiles and/or bombs. Each stage in the game was named after a letter of the Greek alphabet. In certain versions of the game, there is an additional level called "Infinity" (represented by the infinity symbol) which occurs after Omega, after which the game repeats indefinitely.

In the NES version, after defeating the Omega target, the player can see a black screen with Tecmo's logo, announcing the future release of the sequel Super Star Force. After that, the infinity target becomes available and the game repeats the same level and boss without increasing the difficulty.

Reception
In Japan, Game Machine listed Star Force on its December 1, 1984, issue as the fourteenth most-successful table arcade unit at the time.

Sequels

 * Super Star Force: Jikūreki no Himitsu, released in 1986 for the Japanese Nintendo Famicom.
 * Final Star Force, released for arcades in 1992.

Ports and related releases
Star Force was ported and published in 1985 by Hudson Soft to both the MSX home computer and the Family Computer (Famicom) in Japan. Sales of the game were promoted through the first nationwide video game competition to be called "a caravan", although it was not the first event of its kind organized by Hudson (they had previously promoted Lode Runner with a similar event).

The North American and European versions for the Nintendo Entertainment System (NES) were published two years later, in 1987, with significant revisions, and with Tecmo credited rather than Hudson on the title screen and box art. According to Keiji Yamagishi, the NES version was created separately at Tecmo and is distinct from the port released for the Famicom by Hudson. Although the NES version is immediately recognizable as having a great deal in common with the Hudson version released in Japan, there are significant alterations to the graphics, music, and controls and gameplay. Several bugs in gameplay were fixed (debatably making the NES version more difficult) that allow the player (in the Japanese version) to prevent new enemies from appearing ("spawning") by not shooting the enemies already on screen.

Star Force was also ported to the SG-1000 by Sega, X68000 by Dempa Shimbunsha and mobile phones by Tecmo.

In 1995, along with two other NES shooters, the Famicom version of Star Force was remade by Hudson Soft with minimal upgrades for the Super Famicom as part of the Japan-only release of the Caravan Shooting Collection. The same version was also included in Hudson's compilation of NES shooters in 2006 in Hudson Best Collection Vol. 5.

The original arcade version was later added to the compilation titled Tecmo Classic Arcade, which was released for the Xbox. In 2009, the arcade version was made available for download on the Wii Virtual Console for 500 Wii Points as one of the four initial offerings for the "Virtual Console Arcade" category of the Wii Shop Channel (the other three being Gaplus, Mappy, and The Tower of Druaga from Namco).

In 1986, Hudson Soft released the shoot 'em up game Star Soldier, which is considered a spiritual successor to Star Force. The game spawned numerous sequels.