The perspective seems a bit strange when looking at the floor in this screenshot. These rectangles are at least two tiles high, and at the bottom they are in the foreground and at the top they are in the background, with the middle being the part where the player stands on. The problem is the top and bottom don't look any different, which makes the overall effect jarring when compared to the overall visual style of the tileset. The best way to fix this would be to use some sort of gradient where the shading goes from dark to light.

Another issue with perspective here is in the arches in the background. Judging by the floor and the ceiling, the viewpoint here is angled downwards. Because of this, it should be impossible to see underside part at the top of the arches where it meets the wall.