As far as I know, all the demo codes do is give you some extra coins and stones. Why are they banned in all formats, including the colosseums, and what does the ban mean? Does it mean that I can't do a run on a savefile where the code was used?

This is just speculation on my end, is it possible the demo codes will eventually not work years from now?

I was wondering this myself.

My guess is because the demo is technically a separate game from the original, meanwhile a code like "THANKYOUKIRBY" is from within the base game itself, therefore its legal.

yea normal codes in game are allowed the demo codes probably not because they require you to have gotten and beated the demo of the game, which is something very out of the game itself, and as it sint something crucial for the run as it only gives you those coins and some rare stone, and there are allowed codes better than that from the game indeed, so they just decided that because of not requiring having the whole demo just for that

btw what do you mean by "doing a run on a savefile where the code was used" ? you have to create a new file for the run, and it wont have anything with the code activated it doesnt matter if you used it in one file and then do a run in a new diferent file

Not that this would change the status of the rules at all, but the demo codes work without having played the demo. my friend and I tried that out (he played the demo and got the code, let me know about it when i bought the base game). I think David is probably right about the demo codes eventually not working.

oh they work still? okey didnt know that lol