Even if free as beer, the demo version is non-free, in an open source sense. Sure, but you could use any of the many projects built on the open Q3 engine that

Even if free as beer, the demo version is non-free, in an open source sense. Sure, but you could use any of the many projects built on the open Q3 engine that are actually free as in speech. (And maybe child-friendly) Also, to be clear: I find it odd, but still a fun endeavor.