I purchased the Steam version of L4D, downloaded and installed it, but when I try to play with the default settings, all I get is a black screen with words (character names, objects).
I tried enabling useGLSL in the registry (as suggested in other threads), but all that did was give me an oval shape filled with pixels and outlines of objects and people.
The main menu (with animated zombies) and loading screens (both the initial one and the poster with characters when you start a game) appear fine.
I'm running COG 8.1.2 on an iMac with the following specs:
OS: 10.6.2
Proc: 2.66GHz Core 2 Duo
Ram: 4GB
Graphics: ATI Radeon HD 2600 Pro (256MB VRAM)
Any help would be appreciated.