When playing online, I've noticed a few bugs in the game.
One time when playing against Shang Tsung, he turned into my character and did his XRay. Then within 5 seconds, changed back into Shang Tsung and did Shang Tsung's XRay. It's impossible to gain a whole meter again that quick. I know there in Practice mode Tsung can link his and another character's XRays into 1 combo with unlimited meter, but it seems likely that it's possible to do in regular matches also from some meter glitch.
Also I noticed twice a player using Sonya beat me with a repeating standing kick move (don't know what) that was unblockable - I was stuck in the pattern of her pushing me continuously to the side while I'm stuck repeating the frames of me being hit. Unable to do anything, XRay included.
Another semi-glitch is from Kitana in the corner. She was doing a continuous low kick. I was able to block or take damage, but nothing else - I was stuck in the corner. The kick was fast enough to hit me out of every single attack or teleport I tried. The only thing that got me out of it after a while was allowing myself to get hit (the hits were only taking off 2 or 3% each) and collect meter and do my XRay to go through her kick.
Little glitches like these, and other ones found, should also be fixed in the patch. They cheapen the game and make it about exploiting gameplay bugs instead of skill.