Game Rules
You should fight your way to the boss and engage into bringing him down within 3 minutes,
For any enemy that you let flee away from the in-game screen, your mother ship will get damaged and eventually succumb to the damage inflicted,
If your playable character or mother ship's vitality points fall to zero, the game will end.,
Also note that if you fail to bring down the boss within 3 minutes, the game will also end.