I think the upper steps could be lighter. Your first attempt at making them lighter was overkill, but the "fix" dials it back too far.
Also, the bottom step seems to have half the height of all the other steps.
Have you tried having the steps be a couple of pixels taller so that they're not tangent with the tiles above them? I think that tangent is making them feel like they're flat on the floor rather than rising up. Since you have those shadows, I'm guessing it's fine for sprites to break out of those tile boundaries - use that space for the stairs rather than for shadows.