Games revealed to be in development include Resident Evil The Mercenaries 3D (a separate product than Resident Evil Revelations shown at E3).
During the 3DS sizzle reel shown at the event, Nintendo confirms that the 3DS will utilize Mii characters, and transmit these characters (along with other game data) using the local wireless "tag mode" that was utilized in games such as Nintendogs on the Nintendo DS.
The "tag mode" enables the system to talk with other 3DS systems while they are in sleep mode. Data will transfer between the devices no matter which game is plugged into the system. All games can (and possibly will) support this function on the 3DS.
Also revealed: Mii Studio on the 3DS. There are more than 180 million Mii characters out there worldwide, according to Iwata. Mii Studio can be used to make the Mii experience simpler: you can use the system's camera to take a picture of your face, which then can be used as a template to adjust the various Mii face parts to customize the Mii.
Mii characters can then be converted into a QR Code that you can print out or post on a website so you can share your Mii in a different way: friends use their 3DS cameras to take a picture of the code and instantly retrieve your Mii. There is also a Tag Mode Mii Plaza so you can see all the Mii characters you've collected wirelessly.
There also seems to be a cradle that you can set the system into, most likely used to charge the device while not in use. Details on this forthcoming.
The 3DS also appears to have multi-tasking function: you'll be able to hit the home button mid-game and launch certain programs, such as a "Memory Notebook" or pull up your playtime or see the amount of steps you've taken (possibly confirming the system features a pedometer built-in).
The 3DS will bundle a 2GB SD card in with every system to make photo transfers simple. The company will also sell Game Boy and Game Boy Color games through a Virtual Console-like system on 3DS, as well as sell Classic Games in 3D, similar to the tech demo shown at E3.
The system will always be Wi-Fi aware, constantly downloading data from compatible hotspots. Iwata specifically mentioned McDonalds as a place to sync up 3DS data. Japan has many stations all over that already give DS game demos to players and these stations will be updated for 3DS support.
Nintendo has partnered with Fuji TV to distribute free 3D videos to users on an experimental basis.
Iwata admitted during the conference that in the past, very few third party games sell on Nintendo consoles and handhelds. The company will be taking a stronger initiative in helping third-party games sell on the 3DS.
In a developer interview shown at the conference, Namco Bandai's Sakagami notes that he would like to use Tag Mode for rankings and exchanging ghost data in Ridge Racer 3D.
Also in this developer interview video, Yoshinori Ono from Capcom says that they wanted to make a Street Fighter where you can battle anywhere. According to him, you'll be able to use Wi-Fi to receive fight requests wherever you are.
Other details revealed at this conference: Nintendo reiterated that Pokemon Black and White has sold through more than 2.5 million copies since its release a week ago. According to the company that's a Japan record.
The Wii Motion Plus-enhanced Wii Remote (called the Wii Remote Plus) exists, as we reported late last week. Details on that controller are forthcoming. Also, Nintendo of Japan will release a 25th Anniversary Super Mario Nintendo DSi XL system for 18,000 yen next month.
The Last Story ships in Japan on January 27th.
Ed. Note: We originally reported Game Boy Advance games would be available for download. The English translation of the presentation says Game Boy and Game Boy Color games only. The story has been corrected.