Command line parameters (order does not matter):

-full / -fullscreen (Run in full-screen mode)
-win / -windowed (Run in windowed mode [Default])
-dx / -directx (Use DirectX [Windows only])
-gl / -opengl (Use OpenGL)
-16bit (Use 16 bit colordepth)
-24bit (Use 24 bit colordepth)
-32bit (Use 32 bit colordepth)
-w X (Screen resolution width [Default: 640])
-h Y (Screen resolution height [Default: 480])
-noopenal (disable OpenAL audio drivers)
-j ADDRESS / -join ADDRESS (Join a server)
-pw PW / -password PW (join or host with this password)
-map MAP (Host with this map)
-name NAME (Host with this name)
-maxplayers MAXPL (Host with this max players amount)*
-port PORT (Host on this port)*
-rcon PW (Host with this remote control password)*
-lua LUAFILE (Host with this Lua file, rel. to sys/lua)
-nointro (Don't show the intro sequence)
-sys PATH (Use alternative "sys"-folder for settings)
-path PATH (Use alternative working directory)**
-offline / -off (Offline mode, no U.S.G.N. connection)
-nocache (Never load the cached serverlist)
-realport (Use this if players are not able to join via serverlist)
-rconlua (Allow to execute Lua via RCon. WARNING! SECURITY RISK!)