In all honesty thinking about it it's probably not *that* impressive. That means it had a better May than the 3DS or Wii U had in the US, and 3DS was never really a juggernaut platform in the US, it was fairly rare to ever even see two 3DS games ever in the top 10 NPD at the same time. Wii U ... well uh we know how that went.
And NPD doesn't even count digital sales from the Eshop, numbers might be even more impressive now :P
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