Can't say much about how fun the game is since I had to play solo, but the controls work smoothly. It's a well-made game!
Most of the visuals work, particularly the shots, but the ships are really tiny and unnoticeable. They should be the most distinct objects on the screen. Maybe make their colors stronger to contrast the gray asteroids.
Some different death effects would improve the game - the most glaring one is the black hole which seems more like a solid object when you crash into it.