You are a lone astronaut protecting the earth from an invading alien robot army. You have three things to help defend the earth. Your ship that can transport you to random locations, your trusty blaster gun and your wits.
While the attacking robots are numerous they are simple and focus only on attacking you. You can use this single mindedness against them. If you get them to crash into each other they get disabled. You can also crash them into piles of disabled robots. If they get to close you can blast them into dust or use you ship to move away form them to a random location. But beware the ships navigation system isnt the best with all of the interference from the robots and you never know where you will land.