Played a bit of single player Sanctum today. I finished mine on day one, so I tried some mazes on the bridge map. The diagonal design was definitely the most efficient one out of those I tried. It gives good coverage, the penetrating turrets can still shoot in a line, and the bends are so plentiful that the fast mobs are pretty much just fodder. Of course, this means I completed that level. I also got an achievement or two. As for playing with friends, I wanted to do it tonight, but Steam decided it needs to redownload the entire game, so this means 3-4 hours away from it on my connection.