The game was developed by Philip Ulrich, already behind the Ark of Captain Blood. The guy is a genius. This [1] is a short video of him explaining how the game was developed, alas in French only.
What kind of person can block video titled "Dune : il faut sauver la planète des sables | Retrogaming Made in France | ARTE" from being viewed in certain countries?!
Arte itself, maybe? I hit this quite frequently in the opposite direction. Try invidio.us, or duckduckgo. A VPN as a last resort. Or other channels.. I'd have uploaded it, but my upload is very slow today...
The documentary is nice, if a bit short. The target is a general audience, so you might not be missing out that much.
It's not unusual for videos from public TV networks to be region-locked, I think under the premise that it's funded by the tax-payers from a country, so those can get that content for free, but not people from other countries.
[1] https://youtu.be/5nHX_74mjss