Here are more details for the GBA Wii U Virtual Console...

- Use Wii U GamePad, Wii U Pro Controller, or a Wii Remote which has a Classic Controller (Pro) attached to it
- Can enable or disable screen smoothing, and there are two display options for you to choose from. Players can either go full screen or go for the original resolution.
- Colors more vibrant than the Nintendo 3DS Ambassador Games
- Games chug very little
- Look through a scanned in manual in various languages, can keep using it while playing

File sizes
Advance Wars - 62MB
Mario & Luigi Superstar Saga - 63MB
Metroid Fusion - 57 MB
Kirby & The Amazing Mirror - 57MB
WarioWare, Inc: Minigame Mania - 55MB
F-Zero Maximum Velocity - 55MB
Golden Sun - 82MB
Yoshi's Island: Super Mario Advance 3 - 51MB

Full feature here

Source: NintendoWorldReport