Some thoughts:
1) Given that you have clear categories available, it might be worth it to show the name of the category on the reel as well. Sometimes headlines are very broad, and they might not clearly imply the category. I tried a few categories, and in the end forgot which one I was currently watching. -> By showing category indicator you would give additional context for the watcher, on why a specific story is important. I get there's background color doing more or less the same thing, but only if a picture is missing. Color is great for seasoned users (additional pattern would be great for color blind people), new users would probably need clearer information.
2) after the reel ends, you might want to show a final screen, before jumping to the home screen. This way, people could still tap the prev button, if they wanted to recheck some headlines that they missed.