well, first ya gotta get Cloud in the right dress, the one that gets Coreno to pick him over Aeiris or Tifa. Then you have to enter X, SQUARE, TRIANGLE, TRAINGLE, TRAINGLE, TRAINGLE, O+X to make Cloud do the dance of the seven vails while singing row row your boat to a car wash!!
That will revive Zack. Yup *nods*