Bonuses are a game mechanic which by achieving certain objectives, you can gain extra points. It's here from Chicken Invaders: The Next Wave onwards.
Below is a list of these.
Reward - 2000 Points
Objective - Kill chickens in order as they are set to appear.
Reward - Another Life
Objective - Get it every 1M in Rookie, 3M in Veteran, and 10M in Superstar Hero.
Note: M - Million, if you didn't know.
Reward - A Missile
Objective - Get 50 food units, and afterwards it resets the counter to 0 (With a certain Scoring unlockable, you need 100 food units).
Reward - 100,000 Points
Objective - Get your firepower level to 20. It will be awarded even if you did lose a life with having now 1X firepower level and achieving it again.
Reward - Always X * 1,000 Points depending on weapon collected (see here for a detailed explaination), collecting the same weapon again also gives you Firepower
Objective - Collect any weapon present.
Reward - Your current firepower level * 100 Points + 1,000 Points (f.e. 8th firepower level -> 1,800 Points)
Objective - Collect an Atom power-up, or a present with identical weapon as you currently have.
Reward - Number of enemies killed * 100 Points (f.e. 23 enemies killed -> 2,300 Points)
Objective - Kill 4 or more enemies in a quick succession.
Reward - A single or few Atom power-ups
Objective - Have very low firepower on a normal/boss wave.
Note: These Atoms given to the player have their spaceship engine-colored like aura, which prevents other players in multiplayer from stealing it and/or breaking the game.
Super size me!
Reward - None
Objective - Get the largest burger (Quadruple sized Chicken Burger with Tomato, Lettuce, Cheese and three Olives).
Reward - Amount of enemies & obstacles killed * 500 Points (f.e. 58 enemies killed - 2,900
Objective - Kill all enemies in a wave, and don't let anyone survive. This also includes things like Barriers.
Note: You can get this only in certain waves, usually in ones where enemies can escape.
Reward - Number of Chapter * 1,000 Points (f.e. Chapter 11 - 11,000 Points)
Objective - Kill an enemy in less than a second after a wave started.
Reward - A Key, and 11,111 PointsObjective - Collect a Key from an enemy.