Japanese Version
Easy : Designed For Players Unfamiliar With First Person Shooters, No Real Challenge.
Normal : Regular Default Difficutly.
Hard : Slightly more difficult then the normal gameplay.
Extra Hard : Hardest Difficulty, For A Experienced First Person Shooter Player, No Real Challenge.

English Version
Normal : Regular Default Difficutly.
Hard : Slightly more difficult then the normal gameplay.
Extra Hard : Hardest Difficulty, For A Experienced First Person Shooter Player, No Real Challenge.