It's the perspective! As it is here, the rocks look kind of like they're free-floating up. You could probably roll with that though, just add some moss to the very topmost ones for a more reliable platform surface and from there maybe add some extra tiles with floating rock clusters.
To make it a proper hard ground though, you'll have to re-draw it entirely. A good thing to reference would be a mountain path or dry lakebed, to give you a proper idea of the shapes you need to work with! Google mang, it's your friend!