You can edit the overworld and the title screen; however, they won't affect your results. For the overworld, I suggest, you take the special world submap and add some level tiles so you don't spend much time on that.
It looks like I caught this contest just in time :). Though it is 3am here and I was just heading off to sleep, but I'll try to get something started in the morning.
I admittedly, and unfortunately, have had a lot of free time with little to do or worry about, so this should be an interesting temporary change in pacing. Haven't done anything SMW related in... over a year now?? It's always interesting getting back into the swing of it and I'm looking forward to it.
Location: United Kingdom
This is such a great idea! I do not know if I'll be able to participate in time though... I'm also not sure, if I'll go for a Vanilla or a Chocolate Hack... Is the Hack judged in a whole btw or only the single levels each themselves?
This certainly looks like an interesting concept, although I still have a couple of exams and a project report due next week so I'm not entirely sure if I'll have the time to participate. Maybe I'll still be able to put something together, though.
Also seconding the question two posts above me whether or not self-made resources are allowed.
e: given all those themes, will coherence of the levels be judged?