>>32tl;dr: We would rather you not but we will support you and won't remove you if you disclose it beforehand, and are okay with not being eligible for any prices (no promises about those being a thing). Should the rules be edited to add that explicitly?
We would very much prefer games be made
for the jam and the work started at the date of the jam. The time constraint is a large part of the jam experience. If it's something that is public and released before the jam starts and your submission uses that as a base, in my eyes that's equivalent to using a bunch of third party assets. And that is explicitly allowed. Same goes for more game-y game engines (eg. using Luanti - Minetest, PICO-8 / Picotron / TIC-80, etc., no roblox / minecraft through please: that would violate the rules for copyright reasons as we require certain rights to host it). The other interpretation is using the jam to polish / finish your existing project that might incidentally match the theme and rules, we would rather you not do that. Maybe in future iterations. That doesn't spark "start and make for the jam" joy. Rather give us something tiny but unique (however related) than make a large part of a huge project for the jam.
Whatever you make has to be accessible by normal people (presumably without accounts or identity verification) for free and without having to play your existing game first:
sequels / spinoffs are welcome, overhauling mods and addons are at your risk, additional levels / arcs / storylines / mechanics to an unreleased game are likely not desirable.No matter what, we are not likely to delete your submission (unless you blatantly violate the rules - especially around copyright), yet we ask of you to disclose when your project is a continuation / adaptation / modification of an existing or unpublished work, to adjust any attribution, and to not hand prices to somebody who "has not made a dedicated game," and cause fairness-related arguments. That is, if we decide to give out any.