i heard you needed the original game cardridge (supplied with the NDS) is needed for M3 to work. when i bought my NDS i didn't get any game with it (i didn't get the metroid demo with it) does it also work with mario 64 ds or any other game?
Yes, you do need an original game, which you connect to the passkey (normally provided with the M3) and then put into the top of your DS. Any game will work. Depending on what Firmware your DS has you may need to do some extra steps (using a passkey 2), however I had the older firmware, so I can not help you with that. Also, you can flash your firmware with FlashMe, this will remove the need to use the passkey with your DS to load the M3 in DS mode.