The circle type is a better look, but I wonder if the block can be broken down to smaller squares and have the block reveal some of the squares and you move. Or make the big squares with shading. So the closer squares are revealed and the squares a small distance away is a little opaque, the next more opaque and then black.
Otherwise I'm loving the idea. This idea has always been a rpg fan fav, I think.
I look forward to the day I move to MZ and then I'll be sure to make a contribution to your efforts.