Well, the description does tell that they add more difficulty to the missions, removing the "tutorial" part of the campaign to allow a greater PvE challenge.
If you want there is an easier version provided by the modders.
Also, plz don't spam like htat, it's hurtful.
I can even provide you a 3 players version
Almost_AHuman
Ahuman joined
I like games. But, even better is more game per games, so that's why mods are cools.