Yeah for combos to work in this game you have to plan it...Like when I use sub zero I use his little combo where he freezes you and then kicks you, after that I do his ice slide to get like a 26% damage.
But I can't pull it off unless I "plan it" like I have to press y,x,b(he's not done with his animation yet) and then back, foward b and then the combo will pull off correctly
So basically all im saying is plan it out...Works for me