Developer / Publisher
Blue Isle Studios
Details and Conditions
From Blue Isle Studios' Contact Us page:
"For YouTubers inquiring about the possibility of recording and posting footage from our games,
we have no problem whether you are a YouTube Partner or not. Go ahead, you have our permission."
There are no explicit rules against streaming only for paid subscribers on Twitch. I would recommend contacting the developer for certain just in case as an extra precaution.
What it Means
Videos and streams ARE allowed
You CAN monetize on YouTube and Twitch with ads and subscriptions
You SHOULD be able to sell or charge for access to your content (this would include Twitch "subscriber only" streams or selling merchandise)
Any licensed IP or music not owned by the publisher are not covered by this policy