Details and Conditions
Davey Wreden allows YouTube monetization for all Galactic Cafe games. The source below is an archived link from a 2013 post.
"I, Davey Wreden, founder of Galactic Cafe, give full permission for anyone to record, stream, and upload any videos of our games (including Stanley Parable) to anywhere on the internet, and to monetize these videos with ads. No need to ask our permission, go forth, and cultivate revenue. Sow the seeds of your own financial viability. Monetize, and all is right with the world."
The Galactic Cafe website now redirects to The Stanley Parable website. This page no longer exists and a replacement page with an updated statement is not yet available. It is likely YouTube will not consider this as valid permission so you may have to contact the developer directly if needed.
See more details by clicking the "source" link below.
What it Means
Videos and streams ARE allowed
You CAN monetize on YouTube and Twitch with ads and subscriptions
You CAN 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