This is a video included in the extras of a Blu-Ray copy of Back To The Future featuring actors (Billy Zane, C. Thomas Howell, Jon Cryer, and Ben Stiller) in 1984 auditioning for the role of Marty McFly. There’s also clips of Peter DeLuise auditioning for Biff Tannen and Kyra Sedgwick for Jennifer Parker. What might have been! I think they nailed the casting though. Apparently (but not shown in the video) Jeff Goldblum, John Lithgow, Dudley Moore, Ron Silver, Robin Williams, John Cleese, Mandy Patinkin, Gene Hackman, James Woods, and Mark Mothersbaugh were all considered for Doc Brown’s role. Are you thinking what I’m thinking? “Does it involve building a time machine and repeatedly traveling back to the casting and meddling so each actor gets the part just to see how that version of the movie turns out?” Oh what, you’ve got something better to do?