Board Thread:Questions and Answers/@comment-95561-20150315024405/@comment-4093783-20150315025453

As Ned said, nobody's ever tried making a "fan game" but I'm sure it's allowed. I assume it'd have to be an extension of some sort to one of the games already approved (a list of which can be found here), but you'd have to check with Parax. (the wiki president) to be sure.

As far as completely original game idea content goes (implying you mean something along the lines of like an entirely new character or mission or somerthing along those lines), that's what a large portion of the wiki's writings already includes.