HAL21

HAL21 is a vertically scrolling shoot’em up released by SNK in 1985 for arcades. It is considered a spiritual predecessor to the Alpha Mission series. Gameplay is very similar to Namco’s Xevious, with a button for firing regular shots and a button for bombing ground targets, controlled by a crosshair target above the player’s ship. One unique feature from HAL 21 is the bosses, which are composed of multiple small parts. Whenever the player hits a boss part, it flies off from the boss’s body before reattaching.