Halluci-Sabbath of Koishi – takes events into a fantasy world, the main character of which is the modified soldier Satori Komeiji Koishi. He travels around the world carrying out various assignments, receiving money for it. But one day, in the forest, he meets a witch who is trying to find the necessary ingredients for potions. Since then, the couple has been inseparably exploring the vast expanses of the Universe, finding adventures and treasures.

As the story progresses in Halluci-Sabbat of Koishi, the heroes will be able to visit the dense jungle, stumble upon a family of living and aggressive mushrooms, and enter a mysterious place called Gensokyo. The story is told through visual inserts and cut scenes. There is also a dynamic combat system implemented through beat'em up battles. The hero has several specializations from which he can choose. Each of them will affect the abilities available for learning.

To resist dangerous and deadly bosses, you can upgrade attack combinations and new techniques. They are different for characters and can be combined with each other. As you level up, your characteristics improve, your health increases, and your attack damage increases. Also, there is a system of critical hits, they are triggered during a counterattack and when using the enemy’s weak points. For all abilities there is an explanation with a small visualization.