Hey, I appreciate this game; it's simple and fun for the kids to play. However, I could find a few concerns with this project. First of all, the fire sound has no sync with the bullet. If I keep on smashing the space button, then I could listen to the sound, but the bullet frequency doesn't sync with the sound or the button press. Next, If I keep on firing the bullet, I am able to destroy the enemies outside of the screen where they are spawning, So you also need to have a look into that as well. Moreover, you have to introduce additional elements to the game to make it engaging and keep player retention high.
I and my team would love to check your future games in the near future.. All the best!