It works for me in Mac Chrome. (Version 18.0.1025.165) Basically it is a cube with a map that has 3D buildings on all six sides.
I can see the cube with 3D buildings, but cannot interact with it in any way. Mac Chrome 18.0.1025.165
Check chrome://gpu-internals/
I am using Chrome 18.0.1025.165 (Official Build 132849) on Mac and it works very well.
I have 18.0.1025.165 too, and according to that page, everything is hardware accelerated. Though I have Intel GMA 950 from the long forgotten times of 2007, so that might be it.
That could be, it works on both my ATI 4850 iMac and Nvidia MacBook Air.
Tried two Macs in my house. Neither work in Chrome. Both had black maps and their fans are still running.
I get this also.
Same issue. Canary on a 2008 MacBook.
Oddly, when I zoom in twice, the game is visible. It's not usable, but it's there!