As a Wii game, Pikmin will feature a new day-by-day saving mechanism. The feature will allow you to restart play from any day of your choice, according to IGN.
Predictably, Mario Tennis has been totally converted to function with the Wii remote, allowing for full Wii Sports-style control over swings. In addition to a Wiimote-only mode, the game will also support a Wiimote/Nunchuk controller combination for a full range of character movement.
Both titles are due out in Japan over the next two months. The North American debut of the "Play on the Wii" lineup has not yet been announced.