I'm guessing Gavan would like to protect his work a bit and not just give out licences to do anything you want with it - if others want to commercialise, he should get a fair cut, otherwise it's going to be a hard sell to investors. IMO that's completely understandable. I find it sad that things like non permissive CC licenses are regarded as so bad in the open source community - making a project like this completely open is very hard to do as a full time job because of that.

I will put it up on github soon :) License requires a game key for now, but will be open sourced eventually if I can afford to do so. (see other comment on open source)