No revenue estimate for GOG — its rating/review counts don't calibrate to sales the way Steam's do. The Steam version is estimated at $124.5K — a different platform, not this one.

Sound of Drop - fall into poison -

Nestled in the heart of Tokyo, the quaint little aquarium, Manten Aquarium. Numerous urban legends have arisen from here. On the night of the full moon the waters turn to blood and man faced fish lurk within. Junior high school students Mayu and Himeno came to Manten Aquarium to investigate these urban legends. In the beginning it was fun, but then. They see a glimpse of Mayu’s missing littler sister, Mari. The wheels of fate begin turning as they chase after Mari’s shadow. --Before she realizes it, Mayu finds herself alone and lost in the crimson aquarium. How to play ・Proceed through the story from Mayu’s point of view ・Make choices through the game and choose your fate. Contains ・3 main story routes ・Over 30 endings (Mostly bad) This Game may contain content not appropriate for all ages or may not be appropriate for viewing at work.