The year 2525 is once again under threat as space is invaded by the Fulvalence Groma. Only the legendary Super Jet Plane SYD can save the day and destroy the enemy armada.
Alpha Mission II is a top-down, vertically-scrolling shooter that follows in the footsteps of its predecessor Alpha Mission . When the game begins, the player selects two armours for their SYD, which can be upgraded throughout the levels with additional armours purchased at the end. These armours provide extra firepower to the ship while equipped, but will be destroyed if hit.
The primary weapons of the SYD, a straight ahead laser and falling bombs, can also be upgraded from specific enemies' icons. Ground targets can only be hit by bombs, while aerial targets can only be hit by lasers.