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 $18.3K — a different platform, not this one.

Soul Saga

About Soul Saga is a uniquely challenging rogue-lite with a strong focus on  challenging and skill-based airship exploration ,  rewarding and strategic guild management , and a  world that's literally destroyed over time . Features TONS of characters! Soul Saga has a large cast of characters for you to discover, unlock, and recruit! Strategic Combat!  Soul Saga's unique ATB combat system allows you to position your units in defensive or offense stances to optimize your chances at victory. In addition, every turn has a special buff or debuff granted to whomever acts. By accumulating action points by either delaying actions or taking certain actions, you can control the flow of battle with well calculated strategies! Your own Airship!  Free roaming airship exploration with complex physics gives you the power to explore every nook and cranny of this vast world to uncover all of Medonia's natural and historical wonders! And... WOAH! Watch out there, cap'n! Flying an airship takes real skill, and you can crash that baby right into the side of a big ol' sky island! Meaningful difficulty modes! The heat of battle too hot or cold for you? Then choose from either Cake or Disaster difficulty modes to match your play style and skill level!