It looks like someone else here also thought about killing pumpkins haha. Your game is simple and really fun, I liked the concept, although I wish there was a bit more of a storyline behind the safe area we need to protect
You did a great job implementing the main mechanic, it was functional and easy to understand
One tip I can give you is to use a circular radius parameter when generating enemies around that zone, so they spawn from the center and maintain the same distance from their spawn point to the safe area, regardless of direction. I felt that the enemies coming from above or below were closer to it.
It might also help to reduce their speed a bit to make the game easier, but as I said, you did a good job with your concept
Congratulations on your work, and I wish you the best of luck in the jam!