So I had Portal (via Stream) on my laptop and it ran perfectly, but at some point, probably when I upgraded to Maverick, something changed. I tried running it again and I got the following.
Here's the console output:
This doesn't just happen with portal. I got the new Poker Night at the Inventory game and all the players are invisible. I've tried it with PlayonLinux (using several different Wine versions, Windows versions for both Steam and HL2.exe), manual and Vineyard. I've tried it with and without Compiz. I've tried different versions of DirectX. I upgraded to the X Testing graphics drivers. Still nothing. Something weird is going on.