Super Mario Odyssey character art lead Sho Murata revealed in the translated The Art of Super Mario Odyssey that they were initially thinking of a drastic costume change for Luigi within the mini game, but they ultimately decided against it.
Sadly they did not elaborate on this other look all too much.
Luigi in Super Mario Odyssey
Luigi hosts the Balloon World minigame. We wanted players to feel welcome in this minigame, so we gave him a cheerful and casual attitude, like a performer passing out balloons on the street. We wanted to make it seem like he came directly from the Mushroom Kingdom, so in contrast to the sticker-laden Odyssey, his satchel sports only stickers from the Mushroom Kingdom. One of the stickers is actually out of circulation…
We considered a drastic costume change for Luigi at first, but we ultimately went with a simple look, since it would work well against the background of this game’s world.
I wonder… including the Luigi green, did you notice his balloons are the same colors as Super Famicom controller buttons? To the many fans who were looking to his appearance in the game, know that the designer in charge put a lot of effort into Luigi’s development.
I do like the eye for detail when it comes to the Super Famicom color setup. I actually never even thought of that. But that’s just plain awesome.
