Fictional game mockup

[Iceman404]

Maybe give the ground some more saturation, so it will feel more foreground-ish.
Then maybe make the tiles of grass larger, and the green just a smudge darker.

Also, the character also reminds people of Mario for some obvious reasons, but it/he would probably look more original/remind people less if he was another color besides red or green. (Or, maybe that's just my opinion)