That was great! I love the ending! I definitely did not see it coming.
These are my critiques: #1- The other characters don’t move enough. The guy with the blade doesn’t blink, or shift about in response to the main character’s dialogue. And the guys in the background are totally still. Obviously, they shouldn’t move a lot, or that will distract from the main guy. But they still need to appear alive. #2- Everyone should react to the main guy beginning his attack. It would be cool if the guy with the knife leaned back a bit and looked shocked. #3- The lipsync is a bit off. Try using a large variety of mouth shapes, and contrast between small shapes and big ones.
Other than that, though, great job!