I wasn't sure what level layouts you are allowed to select when you play the game. I have Sonic 3 A.I.R. selected, as it is the one selected by default, but I was unsure if you are allowed to pick any other one, or if you are required to use a specific one. It personally doesnt completely matter to me, but I just wanted clarification.

Hey there.

As per the rules:

"All control and tweak settings are optional, except:

Debug Mode, Infinite Time, and Infinite Lives must be turned off
Big Arms must be set to on for all characters
Sandopolis Ghosts must be turned on"

Often if something is mandatory, restricted in some capacity or disallowed entirely, that's when it's mentioned / outlined in the rules specifically.

EDIT: I was made aware of the fact that the "AIR" layouts do offer you the option of using Tails' path in Death Egg Zone with other characters, (via the addition of a spring that prevents you from falling into a bottomless pit), which makes a bit of a difference in terms of routing.

I hope this answers your question :)

well, since you did say i was free to make corrections, a friendly correction would be that, it isn't noticeable at first, but AIR layouts are faster at least in DE1, since in DE1 you can take bottom route as solo sonic, which you can't do with the OG layout, and besides that, if you turn on the buffed cutscene in AI2, it's also significantly faster than having it off, and yet again, if someone wants to point out other major differences, they're free to do so and it'd be appreciated (and i guess the whole thing about DE1 was already mentioned but knowing that the buffed AI2 cutscene is faster is also probably good to know)