Do I have to pay 11$ for both episode 6 AND season 1 , so 22$ in total?
yes, that's the situation right now. I might bundle them together on a later stage, but for now that's how it works here on itch. If you want another take on it - head over to the Patreon page.
Same here, I just payed for the episodes 1-5 . Do you really want me to pay $ 11 again for episode 6
As mentioned earlier, becoming a Patreon is a better deal if you want to follow the story progressively.