Should i make my game open source? It will be free, but i'm worried about theifs..
(reuploading as their work, or selling)

you could trademark your game and defend yourself from "thieves". But that kinda defeats the purpose of being open source

@JCAP I want to be open-source so players can more easily mod the game (and so I don't have to build a mod API) as well as get help from developers. But I also want to keep the legal rights to the game. I don't care about re-uploads if the person(s) made enough changes to my game, I just don't want anyone to claim straight copies, or slightly edited versions as their own.

@Cyanite then I'm pretty sure trademarking is the way to go. I'm no lawyer so your best bet would be talk to one or check out game developer sub reddits or forums. But what I do know is that if you plan to make your game that way and want to protect yourself then you need to register your game as yours. Otherwise the others can legally reupload your game as is or worse, register it as theirs

@JCAP But lawyers require money D;

You can also use the GNU Open-Source license which should (if I've read it correctly) prevent anyone from reuploading your game and/or just simply monetizing it, but I agree with @JCAP , you should talk to a lawyer

Yeah, you can use gnu or mit license

@AngryDev Will that due me until I have one written? Could be several months..

@moshmage My game will be single-player for a good bit into the future.

@moshmage Again, that takes money..

@Cyanite due you?

@AngryDev As in; will that be "good enough" for now?

@Cyanite probably - I wouldn't trust myself (I'm not a lawyer) but it seems to be the go-to license for your usecase

@AngryDev Thanks. I'll look into it ^~^

@moshmage Free game :P I hate charging people(and being charged) for games. And even if it wasn't, being open source makes it nearly imposible to monetize.

Just include a proper software license and you will be good to go

Seriously, use one of the OSSF or MIT licenses. They've already lawyered up. They're good, legally watertight licenses.

Looks like MIT isn't what i want. I'm looking into GNU GPLv3

If i'm correct, it states that:

Anyone can edit the source, but must document changes if they share their copy.

Copies must be distributed with the original license/copyright notice. (And thus can't caim it as their own)

Source must always be available.

// Is that correct?

I'm reading from > http://choosealicense.com/licenses/

Dont worry mate, your game will be stolen both cases.

A license ist a must have if you open source your game. But keep in mind that even with a license, this does only help if in doubt you are willing to pay a lawyer and​ go through court if someone violates it.
So I suggest if you'r up to make money you should think through how copy cats affect your business model and how you can (afford) defend yourself. If it's just for fun take one of the already existing licenses and trust/hope that everybody respects that, what I think will totally do it.
And btw in some countries (e.g. Germany) lawyers have fixed/regulated rates, so there is no way for a model like "you get x percent of the profit".

@Cyanite that looks good, you might want to make sure it's "share alike" meaning that they can only release the source with this or a more binding license.

@starless That is a requirement of GNU GPLv3.