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 $1.7K — a different platform, not this one.

The Manhole: Masterpiece Edition

From the creators of Myst, comes a great journey full of humour, wonderful music and unforgettable moments. Prepare yourself for a grand adventure in the world of epic wonder and whimsical magic. A world where every character comes to life and every new hallway leads to another wild dream. A word of mystery and magic. The world of The Manhole. Though officially for children, this game is a delightful experience for players of all ages. An interesting exploration adventure for kids Funny characters that can touch a child's imagination A game that mixes education with fun