Congratulations on your first published game! I was able to get a high score of 83. If you want to add more precision to the game, I would consider adding a cooldown timer between shots. That way the player should be more careful with their aim. In the current state of the game, if you point straight down and fire as fast as possible, you can get pretty far.
Once again, you should be proud of your first published game, it is an achievement worth celebrating!