Life Force

Salamander (沙羅曼蛇 / サラマンダ, Saramanda), retitled Life Force (ライフフォース, Raifu Fōsu) in North America and in the Japanese arcade re-release, in Europe known as Life Force: Salamander, is a scrolling shooter arcade game by Konami. Released in 1986 as a spin-off of Gradius, Salamander introduced a simplified power-up system, two-player cooperative gameplay and both horizontally and vertically scrolling stages. Some of these later became the norm for future Gradius games.
Salamander was followed with a sequel in 1996 entitled Salamander 2.