Focus is a matter of deciding what things you're not going to do.

Sharing the code just seems like The Right Thing to Do. It costs us rather little, but it benefits a lot of people in sometimes very significant ways. There are many university research projects, proof of concept publisher demos, and new platform test beds that have leveraged the code. Free software that people value adds wealth to the world.

Because of the nature of Moore's law, anything that an extremely clever graphics programmer can do at one point can be replicated by a merely competent programmer some number of years later.

One of the big lessons of a big project is you don't want people that aren't really programmers programming, you'll suffer for it!

I really think, if anything, there is more evidence to show that the violent games reduce aggression and violence. There have actually been some studies about that, that it's cathartic. If you go to QuakeCon and you walk by and you see the people there [and compare that to] a random cross section of a college campus, you're probably going to find a more peaceful crowd of people at the gaming convention. I think it’s at worst neutral and potentially positive.

I'd rather have a search engine or a compiler on a deserted island than a game.

You can prematurely optimize maintainability, flexibility, security, and robustness just like you can performance.