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 $502.6K — a different platform, not this one.

Alien Breed: Impact

Alien Breed™ Impact is an explosive science fiction arcade-shooter that resurrects a much revered franchise with an epic story, swarms of highly intelligent alien enemies, high-impact weapons, highly detailed and rich environments; all implemented with superb technology in a state-of-the-art gaming experience. Key Features: Alien Breed is back! - An action-packed mix of arcade-shooter, survival-horror and tactical weapons upgrades and customisation. Epic single-player story mode - The single-player campaign mode that follows the narrative of the game through five huge and challenging environments. Single-player free-play mode - A single-player challenge mode – beat your high score on a previously completed campaign mission. Upgrades shop - Search fallen comrades and lockers to accumulate cash, and then tactically spend it on weapons/kit upgrades in the shop. Enemies - Re-imagined and improved Alien Breed enemies.