Difficulty: Easy
Humans are released gradually through a level when a certain enemy or group of enemy ships is destroyed.
These enemies glow green and a flare will fire in the direction of the released human afterwards.
Grab this human before he dies or is captured by a saucer and transport him to a beacon at the top of the screen.
Note: Saving humans grants bonuses and upgrades to your ship, which are needed to survive on later levels