Life Force

Salamander (沙羅曼蛇), retitled Life Force in North America and in the Japanese arcade re-release (see version differences), is a scrolling shooter arcade game by Konami. Released in 1986 as a spin-off to Gradius, Salamander introduced a simplified power-up system, two-player cooperative gameplay and both horizontally and vertically scrolling stages. Some of these would later become the norm for future Gradius games. Salamander was followed with an official sequel in 1996 entitled Salamander 2.

Gameplay
It is similar to Gradius, except that two players can participate in the same game at the same time, the player's new ship appears right in the middle of the ongoing action instead of starting over from some "checkpoint" position, and in some versions you can collect the specific power-up that appears rather than waiting to collect enough power-up pods to activate the desired power-up. There is a total of six levels in the game; the odd-numbered levels are all horizontal, while the even-numbered levels are vertical. At the end of every level there is a boss creature that you must defeat; at the end of the sixth, there is also a series of rapidly closing gates that you must navigate safely through to escape.

Nintendo Entertainment System
Salamander was ported to the Family Computer in Japan in 1987. Instead of being a direct port of Salamander, elements were taken from the original Salamander and the Japanese Life Force re-release, and some elements, such as levels and bosses, were removed to make way for new content. Most of the background graphics and enemy sprites from Salamander, however, are used in favor of those used in Life Force, though the Gradius-style power bar is used in place of the original instant pick-up system. The same year, North America received a port as well for the Nintendo Entertainment System. The NES version is practically identical to its Famicom equivalent, other than not having the multiple endings and being titled Life Force. These ports make use of the Konami Code, which in this instance increases the number of lives from three to 30. The NES version was re-released for the Wii's Virtual Console in North America on February 16, 2009 at a cost of 500 Wii Points.

MSX
The MSX port of Salamander is significantly different than the original and any other ports. New to this port is a graphical introduction that introduces human pilots for each ship, as well as names for each stage. The levels are notably longer than the arcade original, and the player(s) is(are) forced to start from a pre-defined checkpoint upon death of either pilot, instead of starting where he/she left off. After level two, the player can choose the order of the next three stages. In addition, the player can collect "E" capsules by destroying certain enemies. Collecting fifteen will permanently upgrade one of the available weapons on the power-up bar. This port also introduced two entirely new ships. Instead of the Vic Viper and the Lord British Space Destroyer, they were replaced by ships known as the Sabel Tiger and the Thrasher; piloted by human characters named Iggy Rock and Zowie Scott. The story takes place in the year 6709 A.D.

PC Engine
A version for the PC Engine was released on December 12, 1991. Changes include starting from a pre-defined checkpoint upon death (1 Player mode), faster enemy animations, and music being somewhat improved from the arcade version.

Home Computers
Ocean Software on their Imagine label, released licensed versions of Salamander for computer systems by Spectrum, Commodore and Amstrad in 1988. Whilst the Spectrum and Amstrad versions were generally criticised, the Commodore 64 version was highly praised by the critics of the day, particularly Zzap!64. Despite missing two of the six stages, the simultaneous two player mode and gameplay being much easier than its arcade counterpart, the Commodore port is generally considered to be one of the best arcade conversions on this system.

PlayStation and the Sega Saturn
A compilation titled Salamander Deluxe Pack Plus was released in Japan for the Sega Saturn on June 19, 1997, and for the PlayStation on July 6 of the same year. The compilation includes both, the Japanese versions of Salamander and Life Force, as well as Salamander 2.

PlayStation Portable
Another compilation of the Salamander series, titled Salamander Portable, was released for the PlayStation Portable on January 24, 2007 in Japan. The PSP compilation features all three games previously included in the Salamander Deluxe Pack Plus, as well as Xexex and the MSX version of Gradius 2 (aka Nemesis II, which is unrelated to the arcade game Gradius II).