Hmmm. I don't think it's fair if it's a requirement, although it would be extremely helpful, some users might not feel comfortable or committed enough to actually make a video, and somethings are hard to show. For example, "removing dogs" requires removing few pieces of code, and taking perhaps a screenshot of what is supposed to be a dog round, but is a zombie round instead, will not be that much of a help to others. And why would someone record themselves removing a few lines and playing zombies to see if dogs were removed?
My point is, some tutorials are simple, and shouldn't "require" an image or video.
If any users have problems with the script, the right thing to do is to tell the author of the thread so they could fix it.