Ok, I've noticed there are 5 difficulty settings files: easy, normal, hard, tactical, and multi.

In single player, how do you adjust the difficulty level? I've looked and either I am just missing it or it isn't there.

Nevermind, I found a solution.

I wanted to make the game slightly more challenging, but not to the level of tactical. Changing the difficulty files in game.pak after patching to 1.04.1 doesn't work anymore, you have to edit them in the *.pat file.