Hello!
GOG was originally a Polish platform for DRM-free games. Because Jakub, the lead dev behind An Amazing Wizard, is from Poland, and because some Kickstarter players have requested to get the game from GOG:
An Amazing Wizard has an official page on GOG!
https://www.gog.com/game/an_amazing_wizard
It is in the "Coming Soon" state, so, you can wishlist the game there. The full game release would be on the same day as Steam, so nobody gets offended :)
Liya from Erabit