In many aspects of CP it is very hard. In others it is fairly easy. There aren't many easy ones though so that's why I have decided to make this guide. There are 3 difficulty levels to choose from at the beginning of the game: Rookie, Sergeant, and Captain. I'd start off with Rookie and work your way up in ranking just like they do in the "real world."
ROOKIE: There aren't many guys that pop out more than once. Overall it is a lot easier to hit the enemy without shooting right at them.
SERGEANT: A little tougher than Rookie but not a whole lot. There's just more enemies in the shooting gallery parts.
CAPTAIN: Noticably harder than ROOKIE you will find yourself on shooting galleries having to shoot sometimes more than 2 times what there is in Rookie.
This is pretty easy hear just as the name implies, but if you still are having trouble with it here's where the enemies are.