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 $12.1K — a different platform, not this one.

Secret Agent

Owners of Secret Agent HD will get a 25% discount when purchasing Secret Agent TOP SECRET! CONFIDENTIAL! FOR YOUR EYES ONLY! Agent 006, your mission, should you choose to accept it, will require you infiltrate the D.V.S. secret hideout and steal the plans to the ultimate laser weapon, only known as “Red Rock Rover”. You are hereby granted a license to kill. The D.V.S. is a notorious terrorist organization and if they manage to complete the laser weapon, the fate of the world will be too horrible to contemplate. Make sure to visit our supplies chief, P, before you head out as you’ll need to disable a vast security system, bypass electric traps, and overcome a significant number of dangerous thugs such as ninjas, sharp-shooters, knife throwers, and even robotic sentries. One last thing, if you manage to eliminate the head of the D.V.S., there will be a bonus in your paycheck. This message will self-destruct in 6.5 seconds...6..5..4..3..2..1 Secret Agent is a classic full-screen scrolling game where you sneak around a huge map and enter various hideouts. In each unique hideout you’ll search for the laser blue prints, dodge deadly traps, solve puzzles, and blast the bad guys in this classic DOS-era run-and-jump platformer from Apogee! Classic Apogee run-and-jump platforming fun mixed with great puzzles! Hundreds of multi-talented guards such as thugs, ninjas, sharp shooters, and robots for you to overcome! Each hideout has a unique layout and look--night missions, scary castles, and villainous fortresses--it’s a veritable feast for the eyes for the discerning retro gamer!