as long as you credit any original artists/authors of the content you use and you are not requiring money to distribute it you should be free to do what you want. from what i understand you can put a fan-based game together and people can donate to you if they like it but as long as the game itself is free to download or play or whatever then there is no financial gain therefore no commercial copyright infringement issue

Lets say i want to make a game about Naruto, right? so i make this game, and its FREE to play. Am i in the line for a law suite? can i make a website? basically, what has to happen for me to be able to get such a game out there, without law suites, if thats even possible.