Marimo -VS- I.A.S

In 2222 AD, the world's ecosystem changed drastically due to the destruction and pollution of the natural environment on the ground. In addition, unknown mutations occur in aquatic organisms that have taken in "mysterious particulate matter" that has poured from the ground into the entire body of water. Lake Akan, the habitat of Marimo, was also invaded by various mutated alien species and preyed on native species one after another. Spherical marimo, once protected by humans, has been significantly reduced in number, leaving only one small colony now. The few survivors of the spherical marimo have begun to roll to fight the imminent hordes of alien species. A 2.5D shooter with old-fashioned side-scrolling and a way to attack enemies in the background. Fight with lock-on shots that can track up to 6 enemies appearing from the back of the screen at the same time, and forward charge shots that can penetrate enemies and enemy bullets. Defeating many enemies with one attack will increase the score you get, and the final score will change greatly depending on the order in which you defeat the enemies.