For those of you who are getting the following error when trying to launch Portal, there is hope! Unless you’re running it under Boot Camp on a MacBook, if that’s the case you’re screwed.
Hanging application hl2.exe, version 0.0.0.0, hang module hungapp, version 0.0.0.0, hang address 0x00000000.
Just add the following to the end of the Target path of the Portal shortcut:
-dxlevel 81 +mat_forcehardwaresync 0
You can do so by right clicking on the Portal icon and selecting Properties.
After you’re finished, it should look something like this:
Steam.exe -applaunch 400 -dxlevel 81 +mat_forcehardwaresync 0
Now click Ok.
Please note this fix is only relevant for launching Portal using the desktop shortcut, this will not fix launch problems with launching Portal from within Steam.