Image & Form is looking into a cross-buy discount for SteamWorld Dig. If such a thing is implemented, those who own the 3DS version of the game will be able to pick up the Wii U release for a cheaper price.
Image & Form said on Twitter:
@Necroadr The Wii U game will probably be cheaper if you already own the 3DS game. We're looking into it
— Image & Form (@ImageForm) July 18, 2014
Thanks to Adrian Brown for the tip.