different colored "SP" icons to acquire, like a flamethrower and a rotating energy ball capable of piercing walls. Another gameplay feature is the energy bar; Similar to Wonder Boy, players must remain aware of the energy bar, which constantly runs down at a steady pace and can only be refilled by collecting "E" icons scattered throughout the stage. However, the energy bar itself does not act as health, as players can still be killed with a single enemy shot. Various other "SP" items can also be picked up along the way such as 1UPs, a speed increaser, shield and an energy extender that increases the length of the energy meter. The game hosts a number of hidden bonus secrets to be found, which is also crucial for reaching high-scores to obtain extra lives, as well as cameos of characters from other Toaplan games such as Flying Shark, Truxton and Zero Wing. The title uses a checkpoint system in which a downed single player will start off at the beginning of the checkpoint they managed to reach before dying. Getting hit by enemy fire, colliding against solid stage obstacles, falling off the stage or running out of energy will result in losing a life, as well as a penalty of decreasing the characters' firepower and speed to his original state and once all lives are lost, the game is over unless the players insert more credits into the arcade machine to continue playing. Although there is an ending, the game loops back to the first stage after completing the last stage as with previous titles from Toaplan, with each one increasing the difficulty and enemies fire denser bullet patterns. Synopsis In an advanced space era, humanity encountered, traded and formed alliances with many alien races to ensure security. Humanity had been subject to past invasions from hostile outside forces but the alliances Earth forged granted victories in the past. However in the year 2095, Earth had been subjected a to new invasion launched by the alien military force of planet Owagira, with overwhelmingly powerful and sophisticated weaponry than anything Earth's alliance could counter. With the threat of annihilation looming over, Earth's United Nations receive a message from an alien elder within their alliances about the existence of an ultra-elite mercenary unit named "Out Zone" at a remote region of the Milky Way galaxy. Known as "Space Entrepreneurs" and renowned for their