I mean for example suppose I create a unique game and post it to the projects forum. Then someone else saw it and thought, 'oh that's pretty cool, only I could do it better' and then takes the same idea but makes their own version and then ends up selling it. Or, suppose I finish my game and decide it's commercial ready and start selling it. Someone sees the commercial version and decides to make their own version but using the same ideas or story line etc.
Even with a copyright, you are not able to protect this of your game.
You can protect its name, its graphics and protect it from reverse engineering, but you can't protect the ideas for example of the gameplay itself.
But, that doesn't mean that you have a big risk when you go public because it is quite seldom that someone grabs your ideas and makes a commercially successful game.
And, if someone copies your game ideas, this won't be the reason if your game is no success. There is so much more than just finishing a game with a nice concept that you have to do to have success in selling your game.
