Competitive balance is a concept used for good game making in multiplayer,
player versus
player games where different characters have different stats.
Basically, no single character type will be better than the other character types.
So if the character types are warrior, archer, and mage, a game that maintains competitive balance will have archers
beat mages, mages
beat warriors, and warriors beat archers for example.
Note that this is a generalized concept. An archer could theoretically beat a warrior in a fight in the above example, but generally, warriors will have the advantage over archers.
Also known as Elemental Rock Paper Scissors when elements are involved.
*Playing Super Smash Brothers
Brawl*
"So who are you gonna be?"
"I
like Meta
Knight. I'm gonna be him."
"Are you crazy? He breaks competitive balance he's so over powered!"