Game uses three difficulty settings allowing the player to choose from easy, normal or difficult level of difficulties. Various flags use three values to differentiate the difficulty levels like in AIHateDelays or TotalAITeamCap. AITriggers also use these three difficulty levels.
Difficulty Settings as such refers to the three sections of Easy, Normal and Difficult. Difficult level is also known as brutal or hard. The flags used in these sections are Groundspeed, Airspeed, BuildTime, Armor, ROF, Cost, FirePower, RepairDelay, BuildDelay, DestroyWalls and ContentScan.
In single player missions/campaigns, if the player selects to play at easy difficulty level, then the game will use values from [Easy] section for the player and computer/AI gets values from [Difficult] section. If the player select to play at medium/normal level, then both the player and computer/AI will use values from [Normal] section. And if the player selects to play at hard difficulty level, then the game will use values from [Difficult] section for the player and computer/AI gets values from [Easy] section.
In skirmish/multiplay, human player always get the values from [Normal] difficulty section. AI on hard/brutal gets the values from [Easy] section. And AI set on easy difficulty gets the values from [Difficult] section. AI on normal/medium difficulty setting gets its values from [Normal] section.
Fields of RepairDelay, BuildDelay, DestroyWalls and ContentScan only affects the computer player.
In RA2 and YR
Armor, Cost, Airspeed, Groundspeed, BuildSlowdown, BuildDelay and ContentScan are obsolete. FirePower and ROF works for both human and AI players. RepairDelay and BuildTime are used by AI players only. BuildTime is not a multiplier for generic building time period but is a multiplier to TeamDelays value.
A new system with fields like CostBuildingsMult is put in place for Country Statistics but not for Difficulty Settings.