You could add the missing darker grey coloring from the bottom half of the circles at the bottom of the overlay yourself if you're up to it.

Here are some shots of a Flash Gordon overlay that pinsider Stretch7 applied for me:

Original beat-down playfield

For some reason the overlay was missing the lighter red color that is present on the original playfield. This lighter shade is used to great effect to add depth/highlights to the center starburst, and a bit more detail in a couple other areas (circled in pic). Missing Color Circled
Unfortunately, without the highlight/shadow color the center starburst looked really flat in comparison to the original.
Original Overlay
However, once the overlay was applied, a thin layer of clearcoat was put down and then the missing shadow effect was sprayed on. Due to the complexity of the other areas he only did the center starburst this way, but what a difference!

Shadow added, paint still wet
After clearcoat and polish

I'm not 100% certain where the overlay came from (Stretch7 got it) but it looks identical to the one in this thread: https://pinside.com/pinball/forum/topic/found-overlay-for-flash-gordon

It is far from perfect, but much better than what was there before certainly.

- For some reason the top half of almost all the inserts has a slight ring of white between the black outline and the clear insert (misaligned printing?). You can see this if you zoom up the picture in the post above.

- The alignment of the holes and inserts isn't perfect. He did the best he could to align the inserts and it's not too bad, with a few exceptions. See the woodgrain gaps between the rollover switches and the outlines:
Rollover Switches imperfectly aligned
Filled the gaps with black paint which makes them less noticeable.

The top left arrow on the lower playfield also had a large gap between the overlay outline and the actual insert:

He covered the woodgrain between the insert and the outline with some red paint. It actually isn't noticeable now unless you really look closely: Left Arrow Touchup

- The overlay also is not perfectly opaque and shows the original woodgrain through it slightly. You can notice this on the white sections in particular, so you might want to paint the playfield white before applying it, though I'm not sure if that would lighten all the colors or not.

All of this is pretty nitpicky stuff though and it is much nicer than the blown out original. Even CPR playfields can have misaligned outlines and such if the original screens were off (see https://pinside.com/pinball/forum/topic/cpr-centaur-and-fathom-playfields/page/3#post-3346354).

One thing I would suggest though is that you consider contacting pinsider cwg29, he created his own Flash Gordon overlay image and it appears to be of much higher quality than the one I have. See https://pinside.com/pinball/forum/topic/flash-gordon-overlay#post-2807010. He is willing to share his image, it's a bit more work to get it printed, and you need use the waterslide decals for the inserts with his, but I have no doubt the final product would be nicer. Probably less expensive as well.