BallisticNG devs want to bring it to GoG when they reach the 1.0 build in some weeks according to their recent
newspost on Steam :
Will there be any DRM ?
BallisticNG is going to be completely DRM free, it will continue to function as it does now where the game does not require Steam to be running and will only disable Steamworks features when no instance of Steam is found - features such as the workshop, leaderboards, achievements and in the future, online multiplayer.
Will there be any other locations to download the game?
Not for the time being, BallisticNGs downloads are going to be removed from Itch.IO and will instead be replaced with a link to the Steam store. When 1.0 is released we will aim to get the game released on GoG too.
I'm probably a bit biased here because i've donated to this project through patreon and i follow it since ~1 year, but as a wipeout fan this game is for me a real gem, and nothing else on the market approach the driving feeling you have when playing that game.
Started as a free Wipeout fan game on the Steam early acces program, They now want to quit early acces and go for a paid game, so they can continue working on it and add content and features (multiplayer for exemple).
Hopefully soon on GoG, i just created the entry on the wishlist to help push it if needed.
https://www.gog.com/wishlist/games/ballisticng