For each world you pick a character and you can only use that character for that world. But you have to think through which character you use for a world because you can not use that character again for another world. Example: If for World 1 you use Simon then you can not use Simon again for another world. You can use skins but if you pick one for a character then you can't change it, you must beat that world with that skin. Also a skin does not count as a different character even if it plays different. So if example you beat a world with Quick Man you can't go and use Bass for another. There are 8 worlds and 10 characters, so you will use out 8 characters out of the 10 and will not use 2. You can't use warp zones, you must play all 8 Worlds. As you can tell this is a more strategic challenge. You must decide for which world which character would be the best. The challenge's difficulty depends a lot on your knowledge how well you know the worlds and the characters. Here is what characters I used for my playthrough: Spoiler World 1: Ryu World 2: Link World 3: Simon World 4: SOPHIA World 5: Samus World 6: Bill World 7: Bass World 8: Proto Man Characters not used: Mario, Luigi Post what characters did you used in the challenge.