Nintendo 3DS Virtual Console Game Boy Restore Point emulator
The Nintendo 3DS Virtual Console Game Boy Restore Point emulator is an official Game Boy emulator for Nintendo 3DS Virtual Console, with Restore Point support. It is used for most DMG games, even Game Boy Color-enhanced games, but not Game Boy Color(+)-only games.
Super Game Boy is not supported, and Game Boy games are either black and white or pea-green (players can switch between them by adjusting a setting, the pea green is like a real original Game Boy) which has raised some criticism of it. There is no (used at least) Game Boy Color bootstrap ROM support, so players cannot set palettes or use predefined ones.
A hidden setting allows the player to add an original Game Boy border.
Technical details/emulation errors
Overall undefined/invalid/obscure opcodes are not properly emulated. On most cases the program counter will act like it skipped over these, but if the stack was corrupted after the opcode(s), and there is no opcode or combination of opcodes such as ret, and/or stack fixing opcode(s), this will not fix the glitch.
Invalid banks are handled not accurate to the original Game Boy or Game Boy Color, nor are invalid parameters for the stop opcode. However, VRAM access and Echo RAM emulation (based on empirical results) is considered to be accurate (unlike Pokémon Stadium 2 Game Boy Tower).
Support for lesser-known peripherals (e.g. Pocket Sonar) may be non-existent or incomplete, since Nintendo did not distribute these games on the Nintendo 3DS Nintendo eShop.
It may be impossible to run arbitrary code execution in SRAM, but for security and anti-piracy, anti-cheat this is beneficial; yet arbitrary code execution in other areas of the memory map is possible, like original Game Boy/Game Boy Color/Game Boy Advance systems and (most) other emulators. 
- Nintendo 3DS Virtual Console Game Boy Color Restore Point emulator
- Nintendo 3DS Virtual Console Game Boy non-Restore Point emulator
- Nintendo 3DS Virtual Console Game Boy Color non-Restore Point emulator