Jools Watsham of Renegade Kid has released some off-screen footage of the Mutant Mudds E3 build. The 3DS eShop game is a straight-up, no-frills sidescroller in the vein of classics like Commander Keen. The hook is that you can jump into the fore-, mid-, and background planes, a twist inspired directly by Wario Land on the Virtual Boy, perhaps the only good game on that ol' red tumor.
As you can see, it's a pure experience with extremely Game Boy-ish music. But hey! Those are good things! I can't wait to play the full game later this year!