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 $64.8K — a different platform, not this one.

99 Levels to Hell

99 Levels to Hell is a platform shooter with lots of guns, upgrades, magic, traps and monsters to kill. 99 Levels to Hell is a rogue-like-like, which means surviving is key and every time you play you get a new set of levels to play. When you complete 10 levels, the 10th being a boss-fight you unlock a door to the next dungeon. Hidden in the darkness of the dungeons are shops, casinos and elevators. And if you search the dungeons carefully, you might find secret rooms that unlock more of the story, and free new adventurers that you can play as in your next game. Let this great combination of a platformer and a roguelike RPG suck you into its multi-leveled randomly-generated dungeon. You won't be back for hours! 100 randomly generated levels with a wide variety of environments! Beat back the demonspawn with 50+ weapons and powerups! Lots of secrets to uncover, ranging from shops, portals, and even other adventurers.