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

Hammerwatch

Includes the FREE Temple of the Sun campaign! Hammerwatch is a fast-paced hack and slash adventure game, inspired by classic titles of the genre. In the old, mysterious, and not-so-abandoned Castle Hammerwatch a group of heroes must fight their way up through the floors to the very top of the castle, where an ancient dragon awaits them. Not only must they kill the beast, but also get back out in one piece! Bring back your button-mashing hack and slash skills and fight thousands of monsters while avoiding traps, findng secrets and increasing your skills on the way up. Do it yourself or bring three friends for some great fast co-op action! Feel free to launch the editor and build your own adventure with your own graphics, or try out someone else's custom level! Multiplayer notice (Mac): Multiplayer on Mac is still being developed and might not work properly. 4 different classes, with unique features and skills. Multiplayer COOP, online, LAN and local. Mod and editing support.