When I join a game, the screen is very thin and takes up about half the resolution of my monitor and all the colors while in the game is nothing but purple and green.

I went and played around with the video options such as screen size, gamma, and glare but nothing helped.

Anyone else have this problem and/or know what to do to fix it?

Hmm I never faced that problem, but I've got some «possible» solution.

1. Set your resolution to the same as in Windows.
2. Try Escape --> Resume Game : Sometimes my resolution is *** up and by doing this it comes back to normal.
3. Most important : Make sure you have lastest drivers for your video card ! Search with google and you should find them easily.

Hope that helps, I'll post more if I have more ideas.

You've got faulty 3D-card drivers. Happened to me in regular Half-Life, after I installed it but before I got the newest drivers and such.

Actually I had the exact same problem a long time ago with half-life, it is a problem with runnin 32-bit graphics when you can't handle it, OR a res problem as was suggested by n00b101

Heya I had this problem when I put the graphics mode on DIRECT 3D so I put it on OPENGL even if I didnt have that but it worked maybe this will solve it for you as well, or the other way around hghe. Good luck !

Same here...when I used to set my video mode to Direct3D I would get funky colors and textures would blotch together and it ended up I would be staring into 40,000 wall textures.

Switched to OpenGL and the problem was no more!