Let me address the suggestion itself and its constituent parts:
A true Challenge Campaign, against the AI, without involving other players, would require the use of the following settings:
AI Advantage - ON
AI Level - 200
Reduced Squads - ON
Reduced Ammo - ON
Weapon Breakdowns - ON
Vehicle Breakdowns - ON
Mines - ON
Command & Control - ON
Use the Hardx2 setting for all battles
Select one of the 6 major nations for your HQ, but then only buy allied equipment (if British, only buy Indian, for example)
Set Spotting to 70% for Player 1, 100% for Player 2
Use Historic Ratings as designed
There may be some other settings that would make the Challenge more challenging to veteran players, but these are most of the important ones.
1. AI Advantage: with this on, the AI gets some bonus units (free of charge) which increases the difficulty of defeating the AI by a small amount
2. AI Level: questionable as to its true effect, consensus is that the higher the number, the more "crafty" the AI operates
3. Reduced Squads: while this setting applies equally to both sides, the disadvantage incurred by the AI is minimal. A few less men per squad does not make that great a difference to the AI; however, it impacts the player's performance more, because he will typically have fewer units with which to conduct the battle, and can ill afford to lose too many of them. In combination with the AI Advantage and Hardx2 settings, any AI disadvantage from reduced squads is offset and negated.
4. Reduced Ammo: similar to the Reuced Squad setting; in order to apply the handicap to the player, it must also be applied to the AI. However, the disadvantage to the AI is negligible for the most part; the AI does not expend much fire during its Advance, so saving ammunition. Artillery units, on the other hand, will suffer more from this setting for the AI, but again, the use of the AI Advantage and Hardx2 settings will somewhat offset this.
5. Weapon Breakdowns: optimally, only applied to the player; however, both sides must suffer equally from this
6. Vehicle Breakdowns: as with the Weapon Breakdowns, both sides must suffer this
7. Mines: the use of this setting is only to allow the use of mines overall, not to restrict them to only one side or the other. Combined with the player's personal decision to forego use of mines except by in-game placement by engineers, the AI will gain the advantage of being able to place these obstacles at will.
8. Command & Control: use of this setting is pretty much self-explanatory; by itself, it challenges the player nearly half again as much as without
9. Hardx2 setting: this setting doubles the amount of purchase points used by the AI, after it determines that base amount from that spent by the player; as a result, the AI can buy nearly double the quantity of units
10. Selecting one of 6 nations: the interpretation of this restriction seems to have caused some disagreements; let me explain - the game only allows the player to choose one of 6 nations to play the Long WWII Campaign. The use of the "allied" nations does not mean true Allies; in other words, the "allied" nation does not have to be one that the major nation was in reality allied with. The requirement is that you do not use any of the major 6 nations units themselves except for the HQ; I will list some possible combinations below:
- US Army HQ - Philippine or Dutch or Belgian or French or Chinese forces
- UK HQ - Indian or Canadian or ANZAC or Greek or Polish forces
- Soviet HQ - Yugoslav or Polish forces
- Japan HQ - Indian forces
- USMC HQ - Philippine or ANZAC or Chinese forces
- German HQ - Hugarian or Romanian or Italian or Finnish or French forces
11. Spotting settings: self-explanatory, as the lower rating for the player hinders spotting enemy units
12. Historic ratings: while these may be argued to be "subjective" (and I fully agree that they are), they serve a useful purpose in varying the caliber of the individual units. Without this setting on, the overall Experience and Morale ratings would cluster around the default Rating set in the Preferences Screen; there would not be the extended range of variation, leading to less realistic actions on the field. Regardless of the opinions of this facet of the game code, it's use is necessary to provide a level of handicap to the player's forces, especially when used in combination with the concept of selecting "minor" nations to provide the majority of them.
Now, some further thoughts:
1. When I stated that this would be a campaign better for single-player use, I meant that it was intended to be used against the AI, not in combination with other players or in any kind of "tournament" setting. The system recommended by Vahauser is intended to provide a level field for comparing two human players through individual campaign completions, without actually facing each other. The suggestions I made, on the other hand, were made to play a campaign without needing to compare the results against anyone else.
2. The suggestions I made were not intended, in any way, to be taken as a "requirement" or a proven campaign setup; I simply wished to point out some of the settings that were not addressed in other posts about improving the "challenging" aspect of campaign play. It would be wrong of me to say that the settings I pointed to are the "definitive" ones, or that they are the only ones.
Well, that's all.