Mouse

-noforcemaccel > reverts to desktop mouse acceleration settings (more)
-noforcemparms > reverts to desktop mouse button settings (more)
-noforcemspd > uses desktop mouse speed settings (more)

Monitor

-w 640 -h 480 > forces the resolution to 640×480
-w 800 -h 600 > forces the resolution to 800×600
-w 1024 -h 768 > forces the resolution to 1024×768
-full > forces fullscreen mode
-windowed > forces window mode
-freq x > forces the monitor to use x hertz

Video

-gl > run in OpenGL
-d3d > run in Direct3d
-soft > run in software mode

DirectX

-dxlevel 90 > DirectX 9
-dxlevel 81 > DirectX 8.1
-dxlevel 80 > DirectX 8
-dxlevel 70 > DirectX 7
-dxlevel 60 > DirectX 6

Other

-16bpp > forces the colors to 16bit
-32bpp > forces the colors to 32bit
-heapsize x > specify the number (x) of memory to use
-zone x > allocates x amount of KiloBytes of memory for use with the console system
-noip > disables the use of UDP, which is part of the TCP/IP protocol
-noipx > disables the use of the IPX/SPX protocol
-nojoy > disables joystick support (shaves a little bit off the memory footprint)
-wavonly > disables the use of direct sound (only use if you are having sound problems)
-noaafonts > disables Anti-Aliasing of screen fonts
-autoconfig > restores video and performance settings to default
-condebug > logs all console output into the console.log text file