Definitely submit an unfinished game over nothing at all! No one is going to be able to submit a 'complete' game for this, there are always things which could be added or changed or improved upon. Part of the experience of doing a game jam is learning to compromise between your vision and what you have time to actually accomplish. You can use this as an opportunity to understand what should be prioritized.
You still have lots of time before the jam ends, don't give up! A work of art is never truly completed.