Side Scrolling Platform Game Code Review

This video is meant for my class, but if others find it useful, GREAT! I know my code at times might not seem like the bet way to do things, but bear with me please as this is just an example. Also, my code works for the sprite costumes I chose. Do not think that all costumes will work with the same exact code. I also don't show it in action, my students have seen it in action many times, so it will make more sense to them.