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 $11.5K — a different platform, not this one.

Tunnel of Doom

Set Traps: It’s you against the hordes! Boost your chances of success and survival by strategically positioning cannons and barricades before battles begin. Gather Resources: Smash lamps. Destroy crates. Blow up rocks. Search the mine for materials that can be used as makeshift weapons or ammunition for traps. Weapon Combat: If your revolver or rifle ammo is running low… improvise! Throw rocks or glass. Swing your pickaxe. Break out the TNT. Do what it takes to avoid being mobbed by the monsters! Find Perks: Better traps. Improved weapons. More resources. There are 50 perks to discover, each offering an array of stat boosts and gameplay tweaks. Randomly Generated: The layout of the mine, perks, and monster battles change with each new game, meaning every run is different! Dream Mode: Escape the mine to unlock this new, endless challenge. Tunnel of Doom takes place in 1903 at Goldcrest, a small mining town. Due to an unknown incident, the mayor has shut down the mine until further notice. With her husband trapped inside, Angel enters the mine to investigate and search for survivors. Little does she know, hordes of ghoulish creatures are lurking in the darkness… An action rogue-lite hybrid, Tunnel of Doom mixes tower-defense with melee and ranged combat gameplay. Gather resources and use what you find to battle waves of monsters as you try to rescue survivors and escape the mine.