Trunkin on 10 December 2012
@sales2099
Battalion Wars, Pokemon, Metroid Prime: Hunters, Mario Tennis 3DS, and Kid Icarus Uprising all have online MP. I'm sure there are more, but those are just a few off the top of my head.
I dunno why NSMBU doesn't have it, but if I had to guess I'd say it's either because they didn't have enough time to implement it, or because their servers just aren't up to snuff. Then again, it's also possible that they just don't think it matters for the NSMB series.
