Very fun demo. But, I have two issues that I faced while playing it:
1. I can just pause the game and move the mouse to the other side of the screen, and my spaceship will instantly change its position to the mouse's new position after I resume the game. This will create an issue in the future where the player can just dodge the enemies and patterns you created by pausing the game :/
2. Multiple enemy ships can spawn exactly over each other, which almost made me die multiple times.
Fix these issues when you resume working on it, and you'll end up with a great, fun game :)