This jam has some special rules (and a different time frame than usual). Instead of having a set theme and giving you free reign to use whatever tools you want, the roles are reversed: Your game can have any theme, but it must fit the following criteria:
Apart from these limitations, you have complete free reign to create whatever your heart desires. Since this jam is much longer than usual, try to aim for a longer and more complete game; 30 minutes of play time is a good target to strive for.