Devil May Cry 3 Easter Eggs
Hidden mission "number" in cut scenes
In each intro cut scene for each level, the game director included hidden "numbers" that correspond to the action mission level. The hidden numbers in the cut scenes for each level is listed: 
Mission 1 - The number "1" on the pizza box 
Mission 2 - The number "2" on the billboard at the end of the cut scene 
Mission 3 - The burning enemies form the number "3" at the end of the cut scene 
Mission 4 - The hanging banner/flag at the beginning of the cut scene is shaped as the number "4"
Mission 5 - The blood on the wall at the end of the cut scene forms the number "5"
Mission 6 - The explosion at the end of the cut scene leaves the number "6" on the ground 
Mission 7 - The blood stain on the wall reveals the number "7" at the end of the cut scene 
Mission 8 - The moon in the background has the number "8" engraved in it 
Mission 9 - The bullet at the end of the cut scene has "9mm" marked on it 
Mission 10 - The blood on the book at the end of the cut scène forms the number "10"
Mission 11 - The blood on the ground marks the number "11"
Mission 12 - At the end of the cut scene, the chain attached to the ceiling is holding the number "12"
Mission 13 - At the end of the cut scene, the wall in the background has the number "13" engraved 
Mission 14 - The number "14" is on the side of the platform, in the pit 
Mission 15 - The branch at the end of the cut scene shapes the number "15"
Mission 16 - The number "16" is lightly scratched on the ground. It's easier to see the number at the beginning of the mission 
Mission 17 - The top of the pillar at the end of the cut scène forms the number "17"
Mission 18 - A paper containing the number "18" quickly flies by in the air 
Mission 19 - As the camera pans to Lady at the beginning of the cut scene, the number "19" is lightly marked on the ground 
Mission 20 - The number "20" is formed by the clouds in the background