Not that I want to encourage you lot into making more fan games but heres a suggestion to gain a little bit more respect. STOP MAKING FAN GAMES OF ALREADY EXISTING GAMES FRANCHISES.
Now dont get me wrong ripping of someone elses characters from a movie or book is still a bit of a grey aera but lets look at it this way.
If your making a fan game of say your favourate movie your target audiance has nothing gameplay related to compare it to allowing you a tremendous amount of freedom.
However When you make say a mario fan game anyone playing it is obviously going to compare it to the original

Look at other examples of this in the game world goldeneye and tony hawk are to examples of existing franchises that had never been made into a computer game giving the games programers a huge amount of freedom to create somthing totaly original and revolutionary but still be familar with their fans.

obviously choosing this path means a hell of a lot more effort is needed to make the game (ie no ripped graphics or music) but at least you'll have a solid basis for your game.

And lets face it who wouldnt like to play decent game versions of 24, neon genesis (big stompy robots rule), or bear in the big blue house.

Anyway I must run the anti fan game peasents are chasing me with burning torches