Article from Capcom-unity:

Cool, now I want some!

Well I don't expect it to go off shelves very fast, like depleting this amount in a few days or something, but yeah, it should sell extremely well, and it's good to have a good supply of it for that reason.

Less than 40% percent of the stocked solo version of the game have been sold, according to figures from Media Create.

The last Media Create sales show up to August 2, that means only a weekend of sales for the title. 520,000 sales in a single weekend is not to be sneezed at, I mean, that's technically much better than Nintendo's latest first party behemoth, Wii Sports Resort. Not bad for a platform often accused of not selling third party games. It also boosted Wii sales to over 4x the usual weekly sales (along with the launch of the black Wii). Wii Sports Resort did not achieve that as it caters to existing owners for the most part. It's been mentioned here and here (and now here). So, I don't know where IGN found the "dark side" in these numbers because it's almost half the first shipment, in a matter of only two days. Too much spin.
 
Edit: Eh, I guess you had seen already since you had a few comments there. We should be getting numbers for Aug 3-9 soon, to see if the sales kept up for the actual week, or if they dropped after the spur of the weekend. I'm confident the initial shipment will have disappeared off shelves.
 
Edit: The game sold 54.36% of its stock including the Wii bundle, so more than half. There's no reason to separate the stand alone version. That probably means it's more sales than the reported 520,000 copies, perhaps that number doesn't include the bundles and they only counted as Wii unit sales instead. I mean, the shipment was more than a million, 54.36% was sold, it should be over 540,360 sales at the very least.