Yes the game gets updated in patreon with a new "build" each month like a new gallery art or animation sadly we didn't got a new build this month because is an animation and they need to work more on it, they also give us news about the game each week and what they have been up to.
If you are wondering why you haven't got anything here in Itchio is not because the rest of the game is patreon exclusive content is because they are working on act 3 before they make it public for everyone, so once act 3 is finished they will release it here in Itchio.
No I cannot say anything about what's behind patreon, sorry. ^^;