About Nintendo:
PC - isn't their platform. They're got no rights to do anything with CM, because my game not copies any their game,
and it's not commercial. If they're will have problems - comes time to publicly disparage a great company.
But let them to make at least one game about Mario on PC. But hey, they do not!
Anyway, Mario Forever(by Softendo) still alive and gonna be better then Nintendo(New Mario Forever 2012), so i thinks
that it is more problem for them.
Ah yea, and i'm living in Belarus, and i don't think, that they're have any influence there.
You need to learn about how Intellectual Property rights work, as everything you have said implies that you have no idea what you are talking about.
Firstly, the platform is irrelevant. It doesn't matter if you are writing a game for a console or the PC. Even if you do a board game, card game, or even a range of ice creams, if you use any of their trademarks or copyrighted images, you are infringing against them and can have legal action taken against you.
Also, it does not matter of your project is commercial or not. In order to protect their trademarks and copyrights, the holders of them are actually required to take legal action against any infringements they are aware of, or they risk losing their IP rights. The only reason that you haven't heard from their legal department is that so far your project is too insignificant to have reached their attention. Should it become popular enough however, they will become aware of it, at which point they have to respond, in order to protect their IP.
Living in Belarus is not going to make you safe from them either. They won't just send cease and desist orders to you, but will also contact your webhost to get your site taken down. And while you may not take these matters seriously, the webhost probably will.