How to run Tonic Trouble under Windows 7

I had the same problem on Windows Vista 64-bit. After some Googling, I found nothing but I did notice that people with Windows XP did not have the same problem. Anyways, here's my solution:

For Windows Vista/7 users, you'll need to run the game in Windows XP Service Pack 2 emulation mode. Navigate to your Steam CoD installation: C:\\Steam\steamapps\common\call of duty Right-click on CoDSP.exe and click Properties In the Compatibility tab make sure the "Run this program in compatibility mode for:" is checked and change the drop-down to Windows XP (Service Pack 2) Hit Apply and the OK

After this, I was able to change the brightness from in-game without a problem. If this still won't help, try running it as an Administrator. You can follow the above steps but the checkbox is further down in the Compatibility tab.

I had that problem in Win7 too. You can either check Windows XP compatibility mode in the shortcut or .exe file properties, or right-click the game shortcut and select "Run as administrator"