I kinda agree with RabidAlien. Looks perfect to me. I can't see any missing pieces... even after you mentioned them. Looks like an outstand job to me.
Something you may want to try, If I spray paint my backer board black and then hit it with a clear while it is still tacky, the result with cause the black to crinkle giving it a texture. This doesn't work on all projects (esthetics wise) but I have had a few that I did it intentionally with pleasing effects. I have also had rattle cans of paint that seem to cure at different intervals, even from the same case... some as long as a couple days.