Interesting, though the Steam and PSN releases are surely too recent to be taken as large factors there. Wii U version came out months ago though, and got great advertising space on the eShop.
To those here pretending this game basically had no competition on the 3DS, it came out right after Mario Kart and 3D Land, right in the middle of the Pushmo / Mighty Switch Force / VVVVVV / Sakura Samurai / Dillon's Rolling Western wave of eShop releases (all of those games were critically well received and released within a 10-week period in late 2011-early 2012).
The Wii U is where the game had no competition. It was released in June, when there hadn't been a significant eShop release since April and wouldn't be another until August, and only Game&Wario and New Super Luigi U from Nintendo in the general vicinity of its release, with exclusive additional content not available in the 3DS version.
This reminds me of Gunman Clive, which sold more on 3DS than on iOS, Android, and PC combined (the developer basically confirmed that the numbers are around 200k in the eShop, 50k everywhere else).
Anyway, good news for 3DS, great news for Renegade Kid, I'm happy for them. Looking forward to their next few games; they're going to have a big year.
EDIT: Also, Jools commented last week about sales on Steam: "Doesn't look like we're going to get rich from Mudds on Steam. 1900 copies sold. 1400 at 50% off. 442 at 10% off. 58 at full price. Sigh." It seems the game has already been on sale for 50% off.
