Your game gives off that old school arcade feel. I like that most of the enemies to hit move back and forth to simulate fly patterns. Similar to Galaga, I think it'd be fun to figure out how to code a pattern for the enemy spawns to draw out different fly patterns on each level. As such, a great addition would be add harder levels. The motion to move the paddle with the mouse left some fun things happen. Due to the paddle colliding with the edge of the canvas on the right side, but the paddle was able to fully be off on the left, it left a small frame for the ball to land on the paddle, but still count as a loss of life. The ball would respawn from the center, and I think it would be cool to restart the ball from the paddle itself. I had a thing happen a few times where if I moved the paddle at just the right time, the ball would ride the paddle. I was extremely amused by this, as it allowed for a reset of where the balls projected path would go. You're sound effects are good. Thought the game was well balanced. Good job!