I'm sure not every fatality is in here, because marketing, but this video includes most of Mortal Kombat X's gruesome finishing moves. You should not watch these at work.
Or at home, if you're at all squeamish about faces being sliced off and brains falling out and tongues wobbling around pissing out blood. I mean, look at this:
The video also includes some of the game's x-rays, brutal moves that give you a little in-round payoff:
You can see them all below.
Oh, and reminder: yes, the game also has brutalities.