It doesn't seem like it but your game will be rated based on your implementation of the theme and it also might be removed if they suspect you of starting your game early. I don't know their policy, but you might want to check the discord for a faster answer.
Generally the theme is a requirement, it helps ensure people made things during the jam without starting ahead of time and generally is a fun challenge. In many jams, such as this one, it is part of your game's rating. I can't say for sure if it's a must for this jam but i can say, I'm a firm believer that limitations breed creativity and implementing the theme helps me come up with ideas I might not otherwise think of.
