It's seems like you already have realized your mistakes. Ironically enough your outro was extremely anti climatic. I would suggest that you try to produce a proper intro because I was literally staggered by the intro. This could be a nice chiptune song if you had a grasp on what you wanted. It seems like honestly you rushed through the song imo. Still you shouldn't let this clutter ruin the whole song. As you said there were 1 or 2 good parts to this song. I would suggest cutting out everything except those parts and start the song again scratch.
Still practice makes perfect so don't expect to have a perfect song right away.