Space Defender

You are a pilot of a spaceship, who needs to protect earth alone against overwhelming alien attacks. However most of the time you must stay in the earth orbit, moving around earth to block the attacks.

Besides regular attacks, you even face burst waves of enemies, as well as a boss fight. To stand a chance, you must use whatever you can.

PS: there is 'a' keyboard button which immediately calls the boss fight. uh oh I already told you :D