1: One of the most interesting Rocky facts was that Susan Sarandon auditioned for the role of Adrian. She didn't get the part .This had nothing to do with her acting skills. They thought she was too pretty for the role.The role finally went to Talia Shire.
2: The scene that involved Rocky and Adrian kissing in Rocky's kitchen was originally not scripted the way it was shot. Talia Shire had contracted the flu and was worried about getting Stallone sick, so she was very hesitant to kiss him. Her hesitation and behavior was actually such an improvement over the scripted scene that they decided to keep it. Indeed, this scene has become Stallone's favorite scene in the entire Rocky saga, and both he and Shire see the scene as a 'birth-scene' for Adrian, where she is awakened to a new life.
3: Rocky's dog Butkus was actually Sylvester Stallone's dog in real life.
4: According to Burt Young, during filming of the scene where Paulie walks home drunk, an actual drunk wandered onto the location and told Young he wasn't acting drunk convincingly, so Young asked the man to demonstrate it. Young then copied the man's actions for the scene.
5: The movie was shot in 28 days and along the way there were few blunders which could have proved costly.But they were intelligent enough to incorporate these blunders in the script and they manged to get away with it.
6: One of the biggest blunders of Rocky was the huge posters of both Apollo Creed and Rocky that were hung up at the Philadelphia Spectrum. After convincing the producers to front the cash to hire an artist to paint the posters, pictures of both Stallone and Weathers were taken to be sent to the artist. However, Sylvester wasn't wearing the right boxing shorts.The paintings came back with Rocky wearing red shorts with a white stripe. Stallone was actually going to wear white shorts with a red stripe during the fight.
Not having enough money, the producers and director suggested they add this blunder into the story. It would further emphasize the character's plight that nobody really cared.And it worked. In the scene where Rocky points this out to the promoter, Mr. Jergens, the day before the fight and Jergens says,"It doesn't really matter, does it? I'm sure you're gonna give us a great show,"you feel even more empathetic towards Rocky. Stallone later wrote that scene into the script to cover up the goof.
7: The baggy robe that Rocky wore was also a goof. The costume department sent that robe the very day of filming of the fight scene and it was too large for Stallone. With no time to replace it or alter it, Stallone wrote in the dialogue in which Rocky points out the baggy robe.
8: The intimate and extremely charming first date was first written with Rocky and Adrian talking in a restaurant. John Avildsen (the director) didn't like this, telling Stallone that placing them in a scene like that was too static. Avildsen suggested that they go bowling or ice skating or something. Stallone liked the ice skating idea and rewrote the scene. However, he rewrote the date scene with the skating rink crowded. The producers said they had no money for professional skaters, extras, and to scrap the ice after every take.
10: When shooting the scenes in the meat-locker where he punches the slabs of beef, Stallone punched the meat so hard for so long that he flattened out his knuckles. To this day, when he makes a fist, his knuckles are completely level.
11: Frank Stallone,Stallone's father, has a cameo playing the man who rings the opening bell of the Creed vs. Balboa fight. Sylvester's younger brother, also has a cameo playing the lead singer of the street band.
12: The movie's line "Yo, Adrian." was voted as the #80 movie quote by the American Film Institute (out of 100).