difficulty levels

[Wou Mugen]

how does the options difficulty control work?  it never changes anything about the chars

is there a way to change the character's difficulty with options?

[VictorCYBR]

It depends how authors code their AI.
Some authors make the AI more or less agressive depending on the difficult you set. An example:

trigger1 = (ctrl || StateNo = 52 || (StateNo = [100,101])) && Random < (100 * (AILevel ** 2 / 64.0))

Random in MUGEN is a number from 0 to 999. Rounded to 1000, 100 out of 1000 is 10%. So, in short:
If the difficult is 8, the AI has a 10% chance to use the move;
If the difficult is 4, the AI has a 2.5% chance to use the move;
and so on.

Also this only works on MUGEN 1.0 or above.

[Wou Mugen]

will it work on ikemen?

[Cyanide]

Would hope so. If the character has no inbuilt ai it affects how often default mugen button mashes.