In addition to Famicom Wars (Famicom/NES) & Millon's Big Adventure (Famicom/NES) as @Tsuchinoko stated, these are the "3DSware" games Japan is getting:
- Samurai Sword Destiny (UFO)
- Zombie Slayer Diox (UFO)
- Space Harrier 3D (SEGA)
- A new BlazBloo game (spinoff of the BlazBlue fighting series. the first was DSiWare)
- Some sort of BMX platformer
man it's times like these I wish I had a Japanese 3DS

A download play feature for SMB3.What does this feature apply to though?