You don't, Game developers and publishers do not accept unsolicited ideas or designs. They can't take the risk of you submitting an idea that they may have already thought of independently, and then you suing them if they develop that idea without your involvement or consent.
In conclusion, patent protection is possible for previously known drugs being repurposed for new indications. The best chances for patenting repurposed drugs occur when care is given to initial experimentation to establish the usefulness of the drugs and for identifying any unexpected properties of the drugs.
When you are ready to start putting the game out there, put a copyright on everything. That's the copyright symbol, your full name, and the year. Put that on every card and on every page of instructions and on any other printed materials: ``(C) scullery_plateau 2015''. Just like that.
To obtain a patent, an inventor should draft a patent application and then submit it to a national or regional intellectual property (IP) office. This process includes several steps and entails diverse costs, depending on the regional or national laws of the country or contries in which the application is filed.
You don't copyright a video game idea. Make the game, release it, then make another one, better. You can copyright names, graphics (game characters and such), but you can't copyright ideas. Your assets are copyrighted anyways when you publish them, without even needing to do anything other than putting the (c) symbol.
The short answer is yes, but with a few caveats. In the United States, patents are not just about gadgets or physical inventions. They can also cover processes, methods, and yes, even the interactive play mechanics of video games.
Games cannot be patented, so you can do whatever you want to the game. What you need to be careful is using the name, or the specific symbols, the artwork, the wording of the rules, etc. Copyright and trademark are the issues, but not the game itself, not way the rules work... those are immune.
To file a patent in Brazil, it must be processed in The Brazilian entity of patents is the National Institute of Industrial Property (INPI). This is the official government body responsible for Industrial Property rights in Brazil being a federal autarchy of the Ministry of Industry, Foreign Trade and Services.
It usually takes between 5-10 years for the President at the National Institute of Industrial Property (INPI) to process an application for registration. Paris Convention priority can be claimed. Once the registration is complete INPI will issue a Certificate of Registration.
An ``idea'' cannot be patented. An ``invention'' can be patented. The concept behind the patent system is that for any given invention, the earliest patent wins. However, in terms of the question you are asking, the CLAIMS are the really important part of the patent.