Super Mario Maker, Nintendo's bottomless user-generated Mario game for the Wii U, lets you create a lot of things. You can put a cannon in a clown car and have the cannon shoot goombas that can fly. You can pack a castle corridor with so many King Koopas on top of each other it'll look like a 16-bit dragon orgy. You can use mushroom power-ups that transform Mario into Sonic the Hedgehog, Retro Game Master Arino, and a Benny. But in the off chance even this feels constraining (or you just don't want to pay for the game) then Brazillian programmer Lucas Emmerick has just the alternative for you.
Super Mario ReMaker, Emmerick's free, customizable version of Nintendo's big release, Nintendoes what Mario Maker Nintendon't. You have complete control over colour schemes of blocks and pipes. You can use the snowy backgrounds. You can make slopes. There are no content caps. You have a larger selection of enemy attacks and booby traps. The special outfits can come with unique powers instead of strictly cosmetic thrills, and on that note you can customize the outfits to absolutely anything your dweeby heart desires, Emmerick's demonstration featuring characters from Undertale, Homestar Runner and Lego Island.
If you want to play as, oh I don't know, Eddie Murphy as Gumby, then you can just plug it in yourself, Emmerick stating that while you can try requesting new outfits from him, "Nothing stops you from creating your own costume." One of the major omissions from ReMaker is the ability to use the style of Mario 3, World and New which Super Mario Maker lets you swap between.
Assuming it's caught wind of this little homebrew, I'm sure Nintendo will take Emmerick's game down down. That's what it did to a free Zelda Maker a few months back, so I'm preemptively pouring one out for Super Mario ReMaker. Emmerick himself stated he's not crazy about all the deathrattles over his project, though acknowledging a cease and desist as an obvious risk. So if this sounds like something you can't live without, you might want to download it sooner than later.