It's really difficult to see the shading because the colors are so bright. And while some games are supposed to have bright graphics, too much brightness can be very distracting.
I've included a palette of more muted colors that match the ones you used in your last resource. Just as an experiment, try recoloring it with the palette and see which one you prefer. The colors in the palette are very much pastel, but they would allow everyone to comment on your shading a lot more. The brightness of your graphics right now makes it look like there's either no shading, or it's just off.