First off, there needs be no rules for the features to be included other thatn the basic requirements to play the game. The developer can then add anything he/she wants to make theirs stand out. While "any card game" is a broad range of different games I think it makes no difference, no matter what game is selected there will always be some jerk out there who has to cheat and download someone elses code and try to pass it off as his/her own. But I can assure you that as a judge I will compare any and all entries against code found readily available on the net.