NES games for early 3DS adopters were supposed to be released around the world on September 1, but Japan got them a little early. All ten games (see the full list here) are available now if you own a Japanese Nintendo 3DS.
After I downloaded the games via the "your downloads" tab, I tried out Super Mario Bros. first. Sure enough, it’s letterboxed Super Mario Bros. without a fancy 3D filter or two player support. If you pick a two player game, Super Mario Bros. locks up when its Luigi’s turn. Nintendo will add mulitplayer support via free update when these games are sold for an unspecified price on the Nintendo eShop.
While the NES games do not have save states, your progress is saved if you switch to another application, return to the home menu or turn the system off. The Virtual Console menu has not been fully implemented. It only has two touchscreen buttons: return to game and reset.
Save data for The Legend of Zelda, Zelda II, and Metroid work. Yes, save data for Metroid. The Japanese version was built for the Famicom Disk System and had save files instead of passwords.
Have a North American region system? You’ll be able to get your eShop games soon! When you do give Yoshi (aka Yoshi’s Egg in Japan) a try, it’s a Mario themed falling block puzzle game that didn’t get too much attention since it was released late in the NES’ lifecycle.
Update: You can switch to two player mode in Super Mario Bros. by pressing L+R and Y at the same time. Thanks for the correction, everyone!