Medal of Honor: Frontline/Difficulty levels
From StrategyWiki, the video game walkthrough and strategy guide wiki
There are three different difficulty settings for the game they are as follows (as per game):
Easy - Player is a skilled marksman and can heal fully between missions. Enemies are new recruits.
Normal - Players and enemies are evenly matched and some healing occurs between missions.
Hard - Your enemies are truly dangerous and no healing occurs between levels.
