Rather than repeatedly playing stages of about an hour, you can explore a wide world while carefully raising your character. Wouldn't it be nice to have such an STG!! ...that's the concept of this game. Collect a large number of friends and weapons, travel around the vast world, and save the environment and the world that is declining every day with nothing but war. Compared to the same Lethal Operation "Rei Edition", the balance has been adjusted to be closer to an action RPG. Breaks make it easier to erase a large number of bullets, and the defensive performance increases steadily with level and equipment, so even those who are not good at STGs will be able to defeat a brutal boss that shoots 100 rounds per second without fail!