Finishing Assassin's Creed 2. Only read the following if you've played the game or never intend to play it.
The start of the mission told me to kill the final boss, so I went and found him. The fight began, and I reduced his health to zero. I was thinking 'Yeah, I finally got him'. But wait, he's still alive, and calling for guards. No big deal- I took the guards out, and reduced the guy's health to zero again. So cutscene, and...he's still alive with more guards. So I took out the guards and apparently killed him again, but wait- cutscene, he's still alive and he escaped.
So far I thought I'd killed him 3 times.
Ok so last level. I snuck in and jumped him with my hidden blade (1 hit kill), but no death, cutscene, and now we're fighting hand to hand. I brought down his health to nothing, but (surprise), cutscene, he's still alive and he stabs me. For some reason I apparently have no effect from this, then I followed him into a secret passage. Now we fight again, this time a simple fist fight. I brought hiim down to 0 zero health again, and there's another cutscene. This time he concedes, so I think 'Finally, I'm going to get him', but my character refuses to kill him.
So, in total, I thought I'd killed this guy 6 times, but still lived after each time, and I never ended up killing him.