Ozma Wars

Ozma Wars is a 1979 fixed shooter arcade game, and the very first game developed and published by SNK, who were still known as "Shin Nihon Kikaku" at the time. The game is also known as the second ever vertical shoot 'em up game, after Taito's Space Invaders (which ran on the same arcade hardware), but is also additionally known as the first game with disparate "levels". The game is also notable for being the first action game to feature a supply of energy, resembling a life