Well, there is no really screen shot, ... but i can explain you :
- square of about 20x20 "terrain" (in reality, null with creep) were players can have units to defend, this sqare is arounded with 2quare of high terrain and then water. when the units go on high terrain, the units are called back, to prevent players from flying

- there are as square as players... and the ennemies go sqare on square to the end.
that all for the system, for the defense, i'll MAYBE make a collective mineral gain, for fairer map. Or maybe 2 teams of players, .... i need to think about that. Probaly only ground units that attack and as defense : lurkers, firebats, archons, .... and more
starter : if majority of players (of the team) go to the starter, ennemies come .... that for : make faster than other team, and be better

that makes the fun, if fair teams...
probaly possiblility of wall, but limited... like a cross of cannot wall on the square for ennemies can always pass. I'll probaly add more special units with maybe if i can find good ideas, fun attacks.