These are my twin maps...they share some properties in common:

-2 Players, each located at to top corners
-map is linearly symmetrical

And some aspects are opposite:

-White and Black
-One is easy to expand, the other not

The looks are very good.

I especially like it that there is no unused space, like on many 2-player-maps with the bases situated at top. there is mostly a second route at the bottom that is hardly used.

The expansions placement is also very well chosen, this is a plus point :)

I only think terran will be quite strong here, for the mainroute isn't that large. Early should be quite hard, but middle or lategame is t-game.
Can you wall at the base entrance just behind this bridge?

Cannot, it's prevented by broken rocks. the backyard-expansion is fragile to Mutals and drops, and the natural is very open. T vs P in this map is 0:3 indeed...Terrans must use those little dunes(and the cliffed route, of course) well, I think.

This map looks very good, i really like it. I think a few games on it TvP can be useful to continue the comments for this map.

I marked in the GMCS where I dunno if wall-ins are possible. just behind the broken rocks.
Is it because of firefox that my GMCS-comments are always a bit moved away from the place I put them?

no, ff works like IE.

the place where you click should be the top left corner of your GMCS-comment though, it's not 100% accurate anyway.