tiles need work(although im no wizard myself) and not to repeat but the tiles move up to much. I think the side of the tile should be a similar coulor to the top. Lastly i think the characters are a little to 2-d for the 3-d environment.
Since this is not a real game art its ok (I mean its not used on a game) but if it was to be used you would like to make the tiles lower, so that you can make a stairs... right now it would be a little hard to make a walking animation, you would need a climbing one. Other than that, is awesome! And I am taking this as a reference for my tactical spriting.