Unlock Special Items
In order to unlock the Special Item Functions in the New Age version, you must first accumulate a certain amount of points in the Classic Version:

Barrier Employs a shield to protect your cannon (s) from attack.
you need 20,000 Points

Laser Lets you fire a penetration laser from your cannon(s).
you need 15,000 Points

Rapid Gives your cannon(s) rapid-fire capabilities.
you need 5,000 Points

Speed Up Increases the speed at which your cannon(s) fire.
you need 2,000 Points

Stop Temporarily freezes the invaders.
you need 30,000 Points

Support cannons appear and shoot together with your main cannon.
you need 10,000 Points