Well, it looks nice, but it's mostly images.
You have several errors in the bottom layer image. Notice how when you're at 100%, the indicator points past 100%? Also, you have only six segments between 0 and 25 and 75 and 100, and eight between 25 and 50 and 50 and 75. So your labels for 25 and 75 are not evenly placed in the image. Also, dividing 25% into seven segments isn't helpful. Five would be good, so that it's 5% each, but seven is a bad choice.
But really, you shouldn't be putting the numbers and tick marks in the image itself anyway. They should be generated by the chart. That way, you're certain you won't have that sort of error, and can apply the same gauge in other places without needing to edit the image itself.
The attached isn't cleaned up, and I didn't even touch the image, but it'll give you the idea. The span of the gauge has been changed from 270 degrees to 252 degrees to match the image. Once the tick marks and numbers are removed from the image, you could then expand the chart to fit the gauge. Should look about the same, but be more configurable and less prone to error. I also added a couple colored segments, just to show how you would do that without playing with the image.
The general idea seems sound, though. You can make a guage with whatever image you want as the background, and then just overlay the numbers, tick marks, indicator, and any other configurable details using a chart.
