I agree with Goomba, this tileset is incredibly detailed, too much so. I wouldn't be able to play a full game of this because it would grate my eyes a lot. Maybe Goomba and I share some obscure eyesight problem, but I really doubt it.
I see two situations that are both problems: You couldn't have equally as detailed character sets because the scene would become so busy that it becomes a jumbled mess and it would be hard to focus. However, having less detailed characters would stick out like a sore thumb. Heck, I am not even quite sure what kind of characters would fit this tileset. Right now, it seems that you made the tileset for a characterset that's around the RTP size. The actual RTP would look ridiculous, but that's probably as detailed as you could get at that size.
In fact, this tileset looks like it was once much larger but it was shrunken to fit a 32x32 grid. Is that the case?