The floorobs look just like the bigobs, only scaled down, and thus don't match the isometric perspective of the battlescape. If you look at the floorobs for most guns in X-Com, they look like they're actually laying on their side on the ground. The shadowing also doesn't match the convention in most map tiles, where the north walls are generally lighter than the west walls - you can see that pretty clearly in the lower-right corner of the second image you posted.
My suggestion would be to make the floorobs more disc-shaped to match the perspective, and if you use a lighting gradient on them, make it look like the light is coming from the lower-left corner of the screen. Or just use a more subdued gradient than the one you currently have.