Routine blindness affects as all, you are not alone there. That is why its always good to listen to the opinion of others. It does not take away from what you have done but when you listen to what others say you can then relook at your work with fresh eyes.

Make sure you also look into what I suggested about making the bats shadow with alternating pixel checkered board. You could also do the same with the block shadows in normal game play and it will not take any cpu penalty. You will only used extra space in the 'C' ROM space given you need the same sprite tile drawn 4 times (2 times the same of each with alternating checkered board). If you look at my NeoGeo land tech demo on youtube you can see that in action in the drop shadows and ghost in the main menu. Just make sure you view at 720p60 (browser that supports that).

HPman can defo help you with the spinner situation, thats a good call.