Marimo vs. I.A.S

Marimo vs. I.A.S is a 2.5D side-scrolling shooter set in the year 2222. Environmental destruction has connected the seas and lakes, collapsing freshwater ecosystems. Mysterious particles falling into the water cause sudden mutations and create aggressive invasive species. At Lake Akan, native life is being devoured and the marimo are close to extinction, until one mutated marimo awakens with the power to control oxygen through photosynthesis and rolls into battle to protect its friends.

Side-scrolling combat

You fight invading species using lock-on shots that can track up to six enemies at once, and charge shots that pierce enemies and bullets. Chaining takedowns boosts your score through a combo system, while choosing which targets to prioritize is key to achieving high scores. The game uses simple controls with movement and two buttons.

Stages and difficulty

The game has five stages and a hidden stage, with four difficulty levels ranging from beginner to hardcore. It also includes a tutorial and full key configuration support.

Additional features

• A tense orchestral soundtrack
• An in-game database about real-world invasive species

The game is fictional. Some creatures are inspired by real species, but their behavior and ecology may differ from reality.