20 hours - How big is this composition? How big is each section? Just wondering.
Also, at the end, it'll be even more confusing than it is now - I understand what you're doing, since when something is "finished", that sometimes helps determine tweaks we need to make. Either way, I can tell you that Mario and Toad will need to be darkened - and stop using blending tools. The end result of anyone's work who uses tortillians and paper stumps will only come out dingy and dirty every time. Many folks think that using these is a magic wand to making your work look well blended and really nice, when in reality, that's far from what actually happens. Or at least that's my opinion.
I'm also wondering if an earthquake would cause a river to dry up, especially from the middle, when the fault line is clearly to the left. Plus, do you have a horizon line established?
I'm asking questions and trying to give you some crits, since I don't think the idea is being communicated very clearly. Please don't take my words as harsh, soul-less criticism - I can tell you're serious about drawing both by the work you're doing and the fact that you've invested time in it. I want to see you improve, so I'm just trying to give you food for thought.
Doctors heal you, Artists immortalize you.
"Those who can, do. Those who can't, teach" - bullshit.
The usual staples for anatomy: