I'm going to make an exception for prototypes -- projects jammers may have started previously that aren't playable yet or are in the first stages of development (greyboxing, missing key assets, etc) and that either fit the jam theme or were started during a previous MytholoJam. I'm alright with people recycling and updating their own code, artwork, etc, but I want to discourage a) people submitting games that were already finished previously, and b) people tweaking nearly-finished games that weren't created with MytholoJam in mind in order to submit them to many jams. I hate to exclude anybody from the jam, but this is mostly intended to minimize spam and encourage engagement with the jam itself. The official policy going forward will disqualify any projects that were finished before the jam begins. (This can be difficult to enforce in some cases, but I'd like to keep the jam as accessible as possible to those who are excited to participate.)
Since MytholoJams aren't rated and your project is both a prototype and totally relevant to the jam, I think this is a fair exception, so long as it's available to everyone else as well. This goes for anyone in a similar situation, and I'll add it to the guidelines. Thanks for running it by me!