almost perfect
your only missing a few things.
more types of ships, and control over any one you want, so you can use a testduln i have no idea what you call it.
second, maybe you could let us set up our own stages, being able to alter how many ships are in the fight, if a mothership will be there or not, and control over which ship you start with.
third, you need a campain mode. that would make it completely perfect