Do Nintendo 3ds games work on the Nintendo DSi?
No, 3DS games can only be played on a 3DS.
If they were specially designed for the 3DS, no. There is a small tab jutting out of the side of 3DS games making them unplayable on a DSi. Even if you could fit the cards into a DSi, they would not work because they use 3D technology the DSi cannot utilize. DSi games will be playable on the 3DS though.
Nikmon-Normal (Nintendo Wii, Nintendo 3DS) Nikmon-Red (Nintendo DSI, PC) Nikmon-Blue (Nintento Wii) Nikmon-Yellow (Nintento 3DS, PC) Nikmon-Green (Nintento Wii, PC) Nikmon-Purple (Nintendo Wii, Nintento DSI, Nintento 3DS) Nikmon-Orange (Nintento Wii) Nikmon-Brown (Nintento DSI, Nintendo 3DS, PC) Nikmon-Black (Nintendo Wii, Nintendo DSI)