At various times in Rumble in the Bronx, Jackie Chan is set upon by a sneering biker wolfpack, has an entire grocery mart smashed down around his ears, is dragged through a river like a wounded duck and is flattened like roadkill by an enormous, rampaging amphibious vehicle. Which means that our mirthful hero has everyone and everything right where he wants them. Chan plays Keung, a Hong Kong cop visiting New York City, in this impish comedy/adventure that plunges the lawman into a high-testosterone feud over $7 million in diamonds. "Something's always happening here," Keung's uncle says while showing him the neighborhood. He's got that right.