Make it playable above all else. Worry the most about whether the player can get into the game, perform the actions you want them to, and then get out again gracefully. And even that last part can be ignored in favor of having a couple of working features.

Forget art, forget sound, forget animated UIs and particles and all the other bells and whistles until you have a playable that you're having fun with.

Other Jammers and judges will get it, they know the conditions of the event and will be happy to run through an abstraction of what your game is, rather than needing fully modeled and textured characters with voice acting.

Note

Christopher "Jack" Nilssen is an independent game developer, fiction writer, runner, yogi, and lover who is awake before you in the morning. He runs Dark Acre Game Development, a studio committed to producing a game experience every two months in order to generate market awareness and gain a deeper appreciation for all aspects of the game development processes, both commercial and artistic. He is the author of three books and developer of games such as The Child, Ball of Steel, and Above and Below.