Personally I'd think that in the spirit of how a jam is, Summerlands shouldn't be submitted, since it was started way ago. But I think it'd be fine to add to a collection of pastel games.
I was personally brought in to just set up the jam rather than as the initial idea, but in my experience it is definitely disheartening to see a bunch of highly polished assets next to something which has been done in a weekend.
Perhaps if someone has been preparing something like Summerlands it may be a good idea to add a button which people click to say "Yes this has been made entirely over the weekend" versus "This has had assets prepared beforehand but was programmed over the weekend".