It is exciting to build your first pond. It looks like your actual workmanship is good. The pond is built they way people built them for many years, and many people still build them like that.
My strong advice is to buy Rick Bartel's book The RISE Method. It is available on Amazon for $12.50. You can read the book in about 30 minutes. After reading the book you will be able to criticize you design with your new insight and knowledge.
In my opinion, the goal of a "natural" looking pond should be to look like something you find on a hike through the woods or the mountains. I would say by that definition, the pond is probably not the greatest. If you love it, and it is on your own property then that is what matters. If a customer paid a lot of money for it, they probably could have found another pond contractor that would have created a more aesthetically pleasing pond.
If you read the book, or attend a workshop on building natural water features you will instantly know what I am talking about.
Props for posting and asking for criticism. Hopefully you will gain a lot of knowledge because of it. Good luck!
Here is a link to a thread I started about a pond I built some time ago: