The dirt is fine, bit bland though.. it looks like runny mud or somthing. I dont like the water...
Maybe a dark effect to that level would make it look better, but also where the 'mine rock wall thingy' hit the water.. it looks bad. Need like a water edge tile there.
The house roof over lappying bit looks odd, but I say that to everyone. The brown and blue house looks good, I just dont think it suits that... mine/underground type look.