This mockup is suffering from the same stuff that you zombie thing mockup does. The background is way to plain, for my taste. And I want to see more details! You know the tiles looks way to sloppy if you compare them with the character! The character is cool but he looks kind of stiff if you ask me.. Try bending his knees a bit you know making him looka a bit more relaxed, not like a robot :D

read up on some of tsugumo's tile tutorials if you havent already.

these tiles look ok but they dont take away the grid at all.

i think the character needs more contrast, and the background should be AAed more, it looks too sharp for my taste.

Other than that, awesome job :)

Wow! ^^
I don't like the character (the head is very small xD), but all the other things are great ^_^

See ya!