Alpha Mission II (known in Japan as ASO II: Last Guardian) is a sci-fi vertical-scrolling shoot 'em up developed and released by SNK for arcades (running Neo-Geo MVS hardware) on March 25, 1991. It was also released for the Neo Geo AES and ported to the Neo Geo CD, both for all regions during their respective launch dates.
The sequel to SNK's earlier shoot 'em up Alpha Mission (and the only SNK game in the Neo Geo library to be a direct sequel to an earlier dedicated arcade game), players control armored spacecraft (the Armored Scrum Objects) SYD-RX and SYD-FX in the year 2525.
Along with special power-ups and two different types of attacks (laser beams for air-to-air and missiles for air-to-ground), players can collect pieces of 11 different special armor types to temporarily transform their ships and gain special attacks.
Alpha Mission II has the typical shooting gameplay found in most vertical shooters. The weapons and powers ups in the game is what separate it from most other shooters. Your ship has two ways of firing weapons. Laser fire destroys flying enemies and missiles fire destroys land based enemies. You can collect power ups to increase the power of fire, and you can collect speed power ups to make you ship faster. These are the only power ups however. In most shooters, ships have special power bombs that destroys everything on screen. Alpha Mission II takes a different approach. Instead of a super bomb, you collect three parts of a weapon that connects to your ship. If you collect all three parts, then you can choose the super weapon in the side menu during gameplay. The super weapons each have a meter while in use. Once the meter is empty the weapon is no longer useful. You can also buy these super weapons after each stage. You do this by spending gold or G as it's called in the game. You can collect G during gameplay. You can also get a G bonus after every stage completed. You have a ten second time limit to purchase a super weapon before the next stage begins. The game has 6 levels of shooting action.