In battle you will notice a limit meter. It increases each time an enemy hits you. When it reaches it's capacity, that character can use his or her limit break. A character starts off with a level one limit break. And all but Vincent, and Cait Sith get 8 separate ones. Those with 8 separate ones can get a new limit break by either using it a certain amount of times or killing a certain amount of enemies. So there are two moves for each level and there are four levels. To get the first limit break in a new level you must use the second one in the level you are on and kill enemies with it before you get the new to a new level. So for instance you have cloud's cross slash, which is his second move on the 1st lvl. He must kill a certain amount of enemies before he gets blade beam which is his first in his 2nd level of limit. And to get his 2nd move in his second lvl you must use the limit a certain amount of times. Tifa can use all 8 of her moves in a single use of her limit, Cait Sith only has two limit breaks total. Vincent has one limit break per lvl. limit