Yes, you're still the copyright holder, you retain all rights to your work. The only rights you give up are the ones that you expressly give up as specified in the licensing terms that you give to other people.

You don't have to follow the terms of the license because you own it. You can even distribute it to different people with different licensing terms if you like, or stop distributing a particular version at any time and attempt to delete it from the internet (though if other people have copies, you may have already given them permission to make more copies and continue distributing it...)

In most countries on the planet you can not give up your natural rights in your creation, not even if you sign a contract. There are some significant exception to that, including some in North America.

You'll notice that most "open source" software licenses are licenses (permissions) to use and possibly distribute a work derived from copyrighted code. Some licenses require that you distribute a copy of the sources wit the derived work, but not all do. All of the licenses work by having you, the creator of the work, maintain the original copyright and as the creator, you can continue to distribute the work under any license you please. That includes a license involving the exchange of funds or the acceptance of liability, or dropping a condition of making the code available. Your choice.

Keep in mind there are billion-dollar multinational corporations that do nothing but distribute Free software. Being commercial and being "open source" are orthogonal concepts.

Also keep in mind that enforcing your copyright and asserting control of your code is done through tort law. That means you have to pay lawyers and stuff even in the event of a dispute.

Ooooh ooooh. I wrote a couple of pieces on this.

http://maientertainmentlaw.com/2008/03/open-source-faq/

http://maientertainmentlaw.com/2008/03/open-source-f-1/

I should probably update these, to be honest, but reasons. I have a couple of clients who have "open-sourced" certain components of their game, but generally I've advised them to simply open source the mod tool and not the game itself. Ping me directly for specific questions.

That was literally perfect. Very detailed and everything I wanted to know, thanks!

I may have some more specific questions in future - when you say "ping" do you mean pm? (Sorry I'm clearly not down with the cool kids anymore :P)

yup, just shoot me a PM on here or on Discord, (Cherished#9159), or shoot me an e-mail.