Unfortunately, bad things could happen during a game jam and you should not feel bad for that. This is supposed to be a positive experience, so don’t worry if you didn’t manage to make something bigger or more complex, you have gained experience even from this. And believe me when I say that I can imagine how you’ve felt and that’s not worth it.
That being said, considering that you’ve made this game in only 4 hours is a big accomplishment by itself! Good job!