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 $23.2K — a different platform, not this one.

Gunship!

Fly low and strike deep in the re-invention of the Gunship flight combat franchise. In Gunship!, you're the point man for WWIII -- Russian forces have amassed on one side, NATO on the other in a flashpoint conflict in Eastern Europe. You are about to deploy the most devastating weapon in the inventory of war: the helicopter Gunship! Finesse, raw power, stealth and speed blend in a high-wire balancing act of exacting proportions. In the 21st century, the fate of war can turn on one micro-engagement in the epicenter of action. Features: Separate modes emphasizing realistic simulation or instant action to suit different play styles. Customize your crew and loadout in American, German, Russian, and British helicopters. Enter the fray in 20 unique missions