This is starting to come together quite nice!
You know, something about the perspective has been bothering me slightly though. The way the grass is drawn, it looks odd that character has his feet across the very top of the tiles, rather than "standing" on the green.
The rocks that are there also look out of perspective, because they are completely sideview, but the grass is kind of topdown. I'd suggest drawing a layer of top rocks to remedy this, or make the grass darker near the bottom segments so it's flatter and pops out less.
I hope that makes sense?
I also agree with .TakaM's critiques. More contrast will make sure that features of the character aren't misread as him as having a yellow hockey-stick/tentacle arm XD
To be honest, I thought he had a scary mutant arm too.