you can have one sub-area that is as big as the maximum size of the main area
as far as we've been able to tell, a death = course not cleared. so if i'm the first to play your level and finish it on the second try, the clear rate should be 50%
oh, and i'm fine with auto-scrollers but i LOVE good water levels, i think there's a lot of potential there (see level #2 in the community showcase on the first page)
Cool, gonna check it out later. I think my problem with water stages is the freedom of movement. Makes you think totally different about Mario gameplay.