Those are great legs on Nintendo systems.
Consider that the launch week sales do not include backer reward downloads, while the LTD sales do include those. Nintendo platform Kickstarter "pre-orders" were far fewer than those for PC. Anyway, I ran the numbers and got this --
Sales on each platform after launch week (not counting KS rewards)
Steam: 31.3%
3DS: 33.5%
WiiU: 29.1%
Humble&GOG: 6.1%
Of course, the release on GOG and the Humble bundle inflate PC sales, but based on past trends, I think the 3DS and Wii U base will continue to grow relative to the PC base. Ultimately I expect the situation to be reversed, with more than 2/3 of total sales being on Nintendo platforms. That is, until the game's inevitable release on Sony and MS systems.