Wow, I feel all of this.  Keeping your motivation could be a topic all on its own, to be honest.  I am glad you chose to enter even though you hit that wall!  Keeping motivation - especially when you've overscoped - can be a serious challenge.  I absolutely get it!

As for that moment when you realize the game 'isn't fun'...  that is a tough pill to swallow.  There are plenty of times where I've had to go back to the drawing board for that exact issue.  During a game jam, that is even harder since we're under such a time crunch.  The prototype phase can be critical in terms of that search for the fun.

I hope you will consider continuing development - in this project or others - once you have recovered that motivation.  The inspiration to create comes in bursts, sometimes.  I also completely agree with the idea of knowing when to walk away from something.  Seize it when it is there, but don't force it.  You will get there - and you won't resent having done so! :) 

Would be cool to see this developed further because the concept is fun. Congrats on posting a playable version nonetheless!

Congrats on finishing your first jam, and kudos for posting something playable even if you haven't finished it :)!

Figuring out you're not happy with the idea anymore late into production is a constant danger. I found focusing on learning how to quickly prototype helps with that a lot - if you find your idea isn't all that fun, at least you have more time to pivot.

Hope to see you around for more jams!