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 $44.2K — a different platform, not this one.

Avadon: The Black Fortress

You are a servant of Avadon. The Black Fortress. Your job is to protect the Pact, five nations that have banded together in a fragile alliance. The purpose of the Pact: To hold back the waves of invaders that seek to destroy you. Outside the lands of the Pact, there are limitless threats. Barbarians. Fading, jealous empires. Titans and unspeakable horrors. The warriors and spies of Avadon are charged to keep them at bay, weak and divided. You fight in the shadows, rooting out small threats before they have the chance to grow. Your resources are unlimited, and your word is law. You will serve the keep of Avadon, working as a spy and warrior to fight the enemies of your homeland. As a servant of the Black Fortress, your word is law. Experience an exciting fantasy role-playing adventure and battle a conspiracy to destroy your people. There's a lot of turn-based isometric combat ahead of you! Epic fantasy role-playing adventure in an enormous and unique world. Four different character classes, with dozens of unique spells and abilities. Dozens of side quests, hidden dungeons, and secrets to discover.