Everything you want in an arcade game.
Otherwise, the game conspires to make things as out of control as possible (which is very fun and keeps you coming back). There are enemies that home in one you, that just bounce around, that run away from your shots, and black holes that suck in everything around them. The mayhem just builds and builds until the screen is full of enemies and explosions and particles flying around. It's great fun.
Graphics are very functional, and about all you'd expect from an arcade game. Sound is great, the looping sound track sets the perfect, pulsating and slightly tense mood.
Only wish: Some sort of co-op or online mode.