Watch the gameplay trailer, there is a small bit where it shows a stealth kill *Sneak up , stealthed behind enemy, grab him, slit throat. Profit*
Of course, it doesn't show the rest of the sequence, where the depicted "x6 stealth crit bonus" has only taken half his hits off, and he turns and attacks. :whistling:
(in other words, there's the start of a dramatic animation sequence, but we've got no HUD, we've got no system messages, and we don't have the follow-through and end. Anything we get from that sequence is speculation. Other than the fact that there is a "slit throat" animation.)