Love it...except three things.
The visuals are perfect. The challenge of it is spot on. However. Sound effects: The pew pew is terribly, annoyingly shrill. Please lower the pitch. Think Star Wars blasters. Also there is no sound when a ship is destroyed. A little discreet explosion noise would make an important satisfying difference to the overall game experience.
Another major issue is that changes made to settings are not saved. I have to invert controls and turn off sound effects (until they hopefully change) every time I open the game.
Other than that, it's perfect. It's the space gunner game I've been wanting for months and months.