First thing's first - because of the arcade screen 9:16 ratio, do not make the game full-screen or things will look weird.
Second, I think it's quite a bit of fun, reminding me of the old days playing Galaga. That said, there is some enemy tuning that needs to be done to make it harder to exploit the game and rack up a ridiculous amount of points without risk.
Also, I'd like to implement a high score mechanism.
That said, enjoy!