I grew up on these kinds of games in arcades, so this was great to see - really took me back! Loved the vector graphics look, and the sounds. A nice addition would be more visual feedback when you get hit and lose a life. At first I thought I was able to take a few hits before noticing the lives going away on each hit. The new ship is just instantly there and you don't really know it's a new one. Also, you keep getting hit so you can instantly lose all 3 lives.
That's pretty minor though - overall I really liked it. Really good job!