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 $2.6K — a different platform, not this one.

Hind

Experience a rush of adrenaline by climbing into the cockpit of the Mi-24 Hind, the most highly armored, heavily armed, and fiercest helicopter gunship of the Eastern Bloc. Experience sets of missions including troop deployment, troop drops, and pickups based on actual Russian army activity. You can even see 3D animated models of Mujaheddin guerrillas as they lift SA-7s to their shoulders, ready to fire. Get a taste of what it's like to fly against the best Uncle Sam has to offer. With Hind’s varying levels of difficulty, from free-for-all arcade mode to a highly detailed mission planner, it’s the perfect helicopter simulation game for the accomplished gamer and a novice pilot alike. So, Komrade, is time to strap self into cockpit and find out why is nickname for such helicopter called "Flying Tank,” да? Realistic flight model made with almost fanatical attention to detail that will please even the most demanding sim fans. Play through three high-octane campaigns, including one actually based on the Soviet campaign in Afghanistan in 1980. Detailed battlefields with surprising attention to detail, all the way down to animating individual ground troops.