Difficult

This page should correctly be named "[Difficult]"; it is wrong due to technical restrictions.

This section, along with Easy and Normal, controls the impact the selected difficulty has on the players. This particular section defines the tweaks applied when "Difficult/Hard" difficulty is selected. Here you may alter various multipliers to game aspects. Some only affect AI players, others affect both AI and human players.
You may edit multipliers using the following tags:
Note: n.n means a simple floating point number

Airspeed=n.n  

This is the speed multiplier for all aerial units (afaik not including jumpjets)

Armor=n.n  

This is the multiplier to unit and building armor strength

BuildSlowdown=yes/no  

This tag controls whether the computer builds slower than the human player

Cost=n.n  

This is the multiplier to unit and building cost

Firepower=n.n  

This is the multiplier to all weapons' firepower

Groundspeed=n.n  

This is the speed multiplier for all ground units

ROF=n.n  

This is the multiplier to all weapons' rate of fire

These tags only affect the computer player(s):

ContentScan=yes/no  

This controls whether the AI should consider the contents of a transport when choosing a target

RepairDelay=n.n  

This controls the time in minutes between starting building repair

BuildDelay=n.n  

This controls the time in minutes between starting construction

DestroyWalls=yes/no  

This controls whether the AI should scan for and destroy enemy walls

From tests with modifications including Robot Storm, Future Crisis and Mental Omega, the above settings will affect skirmish difficulty selection e.g. easy, normal, brutal.