I wonder why people just do not try to tell the OP their issues instead of posting useless one-liners.
The OP just might not know how much trouble he is getting himself into.
So I will try.
@OP:
You should, when using stuff like visuals and audio, be 110% sure that you can use it. If not you will always run the chance of some IP holder slapping you with the legal hering.
Write directly to Nintendo and get confirmation that they are ok with you using the name and that stuff and also with the content.
People have gotten lawsuits for their name sounding like that of another.
Better safe then sorry.
Also, the fact that you are asking for donations is probably borderline questionable because many comps allow usage of their material as long as it remains free.
And asking money for additional visual (or like) content might be agains that provision.
If you were doing such for extra features that do not come in conflict with the provisions that might be something different.
Again, write Nintendo and lay out all aspects of your doing. If they say fine, make a copy and add it to the project so everyone can see.
If not you should look over everything again and figure out what you can do to satisfy them.
Remember if you do not use their stuff, you have nothing to fear. Make a clone that does the same thing but does not use the IP and you are good to go.
It can be that simple. (Plus I have seen guys here come up with the best names for games yet. ‘They came from the top right corner’ FTW!!!)
You should not be suprised by the reactions you are getting.
People only have your word you are not doing anything illegal and you can imagine that, with all respect, how little value it has.
The only way to convince us is to have hard proof.
Does Nintendo have some kind of liscence document for their content defining what and how you can use their IP?