Hey! Good job on your game. Here are a few thoughts and suggestions
After killing one enemy, two spawn. At some point, there seem to be more enemies than you can shoot. Since the game has a timer to survive, you might want to consider predetermined enemy spawns or changing controls a little to ensure the game can be finished
but anyways, you did a great job, it works, there is even a menu. My best is 8000 score, 10 seconds