If you purchased Mutant Mudds on PC, you were treated to 20 extra hard bonus levels accessible only after you collected all the gems in the main game. These "CGA-Land" stages required the use of Maxwell's Grannie, who could wield all three of the game's upgrades at once.
Jools Watsham of Renegade Kid previously mentioned that those extra levels would eventually be brought to the eShop original. Now the DLC has a solid date: October 25 in the US, October 18 in Europe. This update will be free, so there's no excuse to miss out.
If you thought Mutant Mudds was too easy, these "CGA-Land" areas will most definitely put hair on your nuts.
FREE Mutant Mudds Update Coming to Nintendo eShop Very Soon! [Jools Watsham's Blog]