It seems there is a lot of confusion about the terms “free software” and “open source” here.
First of all, to me, “free software” and “open source” almost mean exactly the same thing. Seriously, read and compare the official definitions. The differences are actually pretty minor.
https://www.gnu.org/philosophy/free-sw.htmlhttp://opensource.org/osd(I also hope it should be clear to everyone here that this is NOT about price.)
Anyways: The only “real” difference between both terms lies in the motivation under which those terms are usually promoted: Free software advocades tend to argue on ethical grounds, open source advocates don't (they emphasize more on practical grounds; a bit too much for my taste. Whatever.).
Also, a software is certainly neither free software nor open source if one of its key components (in this case: the engine) is not available in source-code form. A non-restricive license is also requirement of
both definitions.
So, if Unity is a requirement of running Voxus, this means that Voxus won't be neither open source nor free software.
If this was clear to you all along, then sorry for annoying you. xD
Anyhow, I (and probably others, too) would be grateful if at least the media files (images, etc.) you (Kenney) have created so far would be released for future subgame authors to play around. I bet there would be a high interest in these files. :)
It is a major falling of the Minetest project.
What else do you expect from a software with a big fat “0” in its major version number? ;-)
But yeah, Minetest still has a long way to go.