From their FAQ

Q: Is the game “Open Source” now?

A: Open Source refers to the Open Source Initiative’s definition, which the current non-commercial license doesn’t meet. Ideally, once we finish another game and are hopefully able to re-acquire certain rights, we’d like to re-license the U3 SDK under the MIT License.

That's great to see. Its a fun little game, worth playing at least once

I guess there's some controversy over this title because certain game mod, server, and content creators were banned while others were given advantages? Not sure. I suppose that would not longer be an issue if the license and source code allows those people back into it, but at the same time if the license does not then it could be used as a trap to lure them into grounds for a lawsuit.