Is the source code actually free though? For example, could I redistribute the source code myself and not take any revenue from the people I distributed it to? Could I make some changes to the engine and redistribute it? How would the revenue sharing work if I did something like that and someone using my version of the engine started making money using it?
I'm glad there's another no-cost video game engine available, but I don't think it qualifies as free software in the Free Software Foundation sense of the word free. I haven't seen the actual license though, so maybe it is actually free. It would be awesome if it was.