Just plain wow.
I don't think I can effectively summarize my awe at the quality and depth of this animation. Considering the fact that they're all bunnies, this is fantastic. I don't mind if there's no Bunnykill 4, this is certainly good enough for me. The excellence of the animation here is too powerful to be undone by the lack of a successor.
I don't think Smoke needed to die. By which I don't mean I think he shouldn't have gotten stabbed. I think Snowball could have at least tried to take Smoke's body with him, because there's no way a cleanly cut wound like that (to the abdomen?) could be fatal in such a short period of time. He seemed to be reasonably far away from the station by the time it blew up, so it didn't look like time was a big factor there, but, uh... The only reason I can come up with there is that Snowball no longer wanted the competition. And might have killed Smoke anyway. ...That's kinda creepy.