No, my point wasn't that small fry aren't worth the resources to pursue. I never made any reference to the size of the audience or whether the game would attract the attention of the IP owner. These are irrelevant in legal terms. My point was that a "real" parody is not worth pursuing seriously. If I were really parodying your game, would you actually sue me? You might threaten to sue, sure. I don't think you'd actually take me to court because you would lose.
Your first post seemed to say "you could be sued, is it worth it"? My response is that anyone can sue you for almost anything, so that is a weak reason not to do something. The real issue is to understand the risk. My point about rational entities is aimed at finding this true risk.
This thread is quite different from 95% of similar threads here, in which the OP wants to outright copy a game. Parody is perfectly protected. I don't think it is right or fair to discourage people from making parodies. They are not mere vessels through which copyright can be evaded, they can be creatively brilliant in their own right.
My advice to the OP is - understand what parody means, legally. If you expect even a small audience, or you want to sell it, definitely get a lawyer for some advice to be sure your planned game will be able to use a fair use defence. You do not need a licensing agreement to make a parody, you do not need permission at all.
Then it is up to you. Someone could still threaten you, but you have enough information to try call their bluff, if you want. If your lawyer says your game is a parody under fair use, the chances are the legal department in any company will come to the same conclusion, and will not pursue through the courts. Risk is a two player game* - this was my point about rational legal entities.
* [size="1"]Legal risk, that is, . Risk, the board game, is a little different I believe =]
Thanks for the replies. I understand a lot better now. I think I'll probably hire a lawyer before I start the game and find out exactly what would be a good idea like you suggested. I should probably also pay a little more attention to how they changed stuff in Spaceballs.