So, what am I missing?
Confidence.
This is a perfectly fine piece, you just need to trust that you're adequate enough to keep making things. As humble as people can be, there still has to be a level of confidence. Your piece is by no means bad at all, and is not missing anything vital. It works. It's simple, effective, and generally good. But I would agree with helm that you should post some other stuff so we can get a better feel for your work. Don't be shy, we're not all bad.