To tell you the truth, I found it annoying that I couln't preview your categories with thumbnails. Let's imagine that you have 50 photos in a gallery, and the photos that really interest me are in the last 10. I am going to be forced to look at 40 images that I'm not overly interested in - do you really think a casual visitor is going to have the patience to even look beyond the first 10? I'm not sure your present layout is scalable for 1000's of photos.
When I was in the greyscale gallery, there didn't seem to be an rhyme or reason to how the controls worked on a mouse click. Sometimes the image would change, other times it stayed the same and then rapidly changed twice. I didn't feel as though I had much control over my viewing experience.
I am using a laptop and because of the screen real estate, I only realised after a while and scrolling that there were some white dots under the photos that seemed to indicate the number of photos.
I enjoyed your photos but not the experience.
Ace Coote Photography