"Simple" and elegant
I like it.
The strange thing is that when you listen to it a bunch in a loop, you forget where the start is. It doesn't feel like it should start on the G. Try starting on the Cadd9 (:27) and see how that sounds to you. To me if feels like the more natural beginning of the progression.
Great stuff. Add a melody and a chorus (or make this the chorus and add a verse) and you have yourself a nice little singer/songwriter bit. :)
It sounds like it belongs in a video game. It's expertly put together, I love it.
Please contact me if you would like to use this in a project. We can discuss the details.