Rami_James: I'm developing a game and trying to find the cost of listing on GoG.
They take a cut of the sales price, like Steam or Epic. I don't know the actual rate though.
However, what amok said.
To get past curation your game should be special/interesting in some way and also rock solid.
If you get the infamous "too niche" reply - it's just their standard "polite" way to say no. It can mean anything from "Really nice game, but we already have enough pixel-art rogue-lights" to "We think your game sucks and you should just do something else like bee farming".