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 $2.5M — a different platform, not this one.

Unepic

While taking a break from playing a tabletop RPG, Daniel, an average guy from modern times, is transported to Harnakon’s Castle. Thinking that he is suffering from a hallucination, he decides that he is going to run the adventure for as long as the illusion lasts. As he explores the castle, fights the monsters within, and even casts potent magical spells, Daniel comes to realize that not everything is as it seems. Unepic heroically combines open-world platforming gameplay with the intricacy and challenge of the RPG. Tweak Daniel’s skills to your heart’s content. Fight a bewildering variety of monsters, from the lowly goblin to the gigantic dragon, with over 100 different weapons. If forbidden magics are more your calling, then 70 spells and magical items will please even the most discriminating would-be wizard. Monsters, weapons, potions, spells, quests, pets, bosses, a giant castle all come together to make a funny story Unepic. If you love nerd-based humor and the RPG munchkin in you is strong, you'll appreciate every last bit of this charming RPG/platformer! Notice: Please note this game contains strong language and extreme nerditry. Player discretion is advised. Includes special content unique to the GOG.com version! A full featured RPG character sheet where you create your custom character builds assigning skill points. Features three different endings, four levels of difficulty, plenty of side quests, and tons of secrets and Easter eggs to discover! It’s dangerous to go alone! Take a pet or two with you or even an ancient malevolent entity who means you much bodily harm!