Bruce Lee actually struck Jackie Chan in the face with one of his fighting sticks. He immediately apologized and insisted that Chan could work on all of his movies after that. Unfortunately, Lee died before he could keep his promise.
The movie was made for $850,000, and took in over $90 million worldwide at the box office.
An extra challenged Bruce Lee to a fight to see if he really was that good. Lee won the fight and sent the extra back to work.
In 2004, this movie was deemed "culturally, historically, or aesthetically significant" in the United States and selected for preservation in the National Film Registry of the Library of Congress.
Jackie Chan: Appears twice in the film. Towards the end of the movie in the big cave fight scene. Lee grabs his hair for a while before breaking his neck. He is also one of the stuntmen that Lee hits when he wields two sticks (according to Chan), and then falls into a pit of acid.