I guess those are the EX attacks that they were talking about using the guard button for?
I also notice that the gauge has a few other things than the X Ray attack on it, but they don't mention those mechanics at all. X, S, and something else. Otherwise this looks like standard MK. I just don't get why the block button? Even if its to activate the X-Ray attacks, why not just make the attacks take two punches or kicks to activate instead of putting in the block button and forcing people to play with it? It made sense when it was a 3-D game, not so much when a 2-D.