As most of you already know, some VC games have special features. Such as SMB3 being able to play 2-Player mode through Download Play and Pokemon RBY being able to trade and battle other 3DS's and connect to Pokebank. So, how does this games work? Is it a modified ROM? Or does it have to do with a special feature in the emulator itself? I'm asking this because my dad just got a 3DS and I want to play 2-player Contra with him, since it is one of my favorite NES games. Do you think it would be possible for me to inject Contra (or any other 2-player NES game) into a SMB3 VC or build my own with a special EXEFS? Thanks in advance.