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 $10.9K — a different platform, not this one.

Slave Zero

It's 500 years in the future. Man and machine are virtually one, and the greatest megacity in the world is locked in a brutal war. Mammoth, biomechanical monsters tear at the sky, and the earth shakes with the full fury of a brutal battle. These are the warriors of the future, when war escalates to massive proportions, and immense power of destruction engulfs the streets. Harness the power, make a difference. Take control. Become Slave Zero! Control 60 feet of raw power as Slave Zero. Rampage through a city filled with hover cars, ground traffic, and screaming humans fleeing for their lives. Protect your allies; steal from and destroy the enemy, while working your way up a 7 mile high city. Crush cars and tanks under foot; climb city buildings or swat hover vehicles while completing mission objectives.