Verified
-overrideBigFile Enables the data folder on the disk to be loaded over any data in the .big files.
-locale <language> Loads the specified <language>.big instead of English.big (or whatever language version you have.)
-mod <modification.big> Loads <modification.big> after the other .big files are loaded, this implies -overrideBigFile.
-luatrace Lua debugging will be outputted to hw2.log. Useful for debugging LUA scripts.
-w <width> Screen resolution width, has to be used in conjunction with correct height.
-h <height> Screen resolution height, has to be used in conjunction with correct width.
-d <int> Unknown, likely BPP.-depth?
-refresh <refresh rate> Changes the refresh rate. Set it to your desktop resolution and refresh rate for quick alt-tabbing.
-fullscreen Enables fullscreen view.
-windowed Enables windowed view. (-- seems to also display debug errors as popups - Tamerlane)
-debug Unknown. but confirmed disabled by relic
-useRandomSeed Used to eliminate MP sync errors. probably deprecated with 1.1 patch
-dumpPlayBalanceStats Unknown, something to do with multiplayer.
Outputs a CSV file containing additional end-of-game stats to the "\Bin\LOGFILES\" directory.
Causes the game to lock up when entering GameSpy.
-quickLoad Appears to load HW2 without alot of graphical 'perks', textures being one of them -Tamerlane
-port <port number> Force Homeworld 2 to use the given port.
-freeMouse In windowed mode free the mouse from being constrained by the window boundaries.
-noInt3 turns off debug code which exits the game with an error. -What? Use proper grammar please.
-lowTex Unknown.
-datapath <path> Sets the data path, where data will be loaded from. (Internally, by default, it is ..\..\Data\)
-filelog Unknown.
-logfiles <path?> Unknown.
-produceHODMemoryInfo Unknown.
-startFleet <int> The files in the scripts\startingfleets directory are Hiigaran00.lua and Vaygr00.lua. Create new ones with different contents called Hiigaran01.lua and Vaygr01.lua. Now you can use the -startFleet 0 or -startFleet 1 to switch between the starting lineups.
-superTurbo Makes the in-game timer go very fast. (Eg, the Hiigaran Mothership moves about the same speed as a Hiigaran Fighter in normal speed.)
-bgSim Unknown. Possibly means "Simulate Background"...maybe BG image is suppressed but not the starfield?.
-noS3TC Disables S3 Texture Compression.
-noDisplayLists Disables display lists.
-nopbuffer Disables pixel buffer. effectivly disables shadows
-noRenderToTexture Unknown.
-noRenderToDepthTexture Unknown. Crashes during load?
-noSoundData Unknown.
-nosound Runs the game without sound. Useful if trying to rule out sound problems.
-noRender Disables display rendering.
-texLoadNoROT Sets preference of 2D DDS and TGA resources over ROTs
-texLoadPreferROT Sets preference of 2D ROT resources over DDS and TGA resources
-texLoadMostRecent Sets preference of 2D resources via file date?
-texLoadAlwaysROT Forces loading of ROT files
-noMipMap Disables mip-mapping. does not seem to work -EJ
-hardwareCursor Enable hardware cursor.
-fragment_program <int> Seems to disable scar and utility scripts in some cases
-nv_reg_combiners2 <int> Unknown. Nvidea shader spec for old cards -SC
-nv_reg_combiners_up <int> Unknown. Nvidea Shader spec only -SC
-nv_reg_combiners <int> Unknown. Nvidea shader all of above Nvidea cards
-env_combine_up <int> Unknown. ATI range cards -SC
-ATI_combine3 <int> Unknown. ATI range cards -SC
-env_combine4 <int> Unknown. ATI range cards -SC
-env_combine3 <int> Unknown. ATI Range Cards -SC
-env_crossbar2 <int> Unknown.
-env_combine2 <int> Unknown. ATI range cards -SC
-GameRules <str> Brings the requested gamerule to the top of the list, in skirmishes and MP (handy if you're doing alot of editing). Requires the gamerule filename, without the extension.
-gameendexec <str> Unknown.
-scriptFile <file?> Unknown.
-syncCheckingLevel <int> Unknown.
-unitCapsMode <str> Unknown. Probably the name of a DATA:scripts/unitcaps .lua to load?
-noVideoErrors Disables error messages caused by incompatible graphics cards, video settings, etc.
-noMovies (or --noMovies?) Skips ALL movies, including story-related ones.
-NoATITOSetting Turn off all ATI and TO (the graphics that appear over units in game). does not seem to work -EJ
-noVBO Disables support for Vertex Buffer Objects. crashes during load ? - EJ
-noHSClip Unknown.
-noHSRender Unknown. May turn off Hyperspace effect rendering?
-noBattleScar Unknown. May disable battle scar effects (scorch marks etc.)?
-battleScar_noHealthCap Unknown. Ship's keep battle scars even when repaired?
-battleScar_noTriCap Unknown. No maximum number of battle scar's? Probably kills frame rate
-syncCheckingLevel <int> Unknown.
-noWinLose <bool> Unknown. Prevent player's from winning or losing...game essentially goes on forever?
-outOfSync <int> Unknown. Causes an Out of Sync error? Maybe just for the heck of it?
-exec <str> Unknown.
Probably executes commands through the command shell (e.g. MS-DOS), like the "execute" function.
-notForPublic Displays the not for public display ui in game, from mission 3 onwards in the campain.
There's a disabled UI screen called NotForPublicDisplay. Maybe they're related?
Possibly, perhaps something related to Beta versions of Homeworld2? - Thought
-silentErrors Disables popup debug windows.
-campaign <campaign name> Select a 'custom' campaign to be used (best used in combination with -startinglevel)
-startinglevel <level name> Select a 'custom' level to load at start up (best used in combination with -campaign)

Screenshots
-ssBW Take black & white screenshots.
-ssBoth Take black & white, and colour screenshots.
-ssTGA Take screenshots in TGA format.
-ssJPG Take screenshots in JPG format.
-ssNoLogo Take screenshots without logo. Nice...if functional

Graphics
-800 800x600 Resolution
-640 640x480 Resolution
-1024 1024x768 Resolution
-1280 1280x1024 Resolution It is really 1280 x 980, if you want 1280x1024 (LCD) go to -w 1280 -h 1024
-1600 1600x1200 Resolution
-d8 8-bit Colours
-d16 16-bit Colours
-d24 24-bit Colours
-d36 36-bit Colours
-fullscreen Starts the game in a full screen - is on by default
-window -w #1 -h #2 Starts the game in a window, resolution #1x#2

-truecolour Uses 24-bit colour with sharper rendering
-d3d Uses direct 3D
-gl Forces OpenGL
-device <sw|fx|d3d> Uses RGL device
-boxes All ships become boxier
-noBG No backgrounds are shown vila...here is the command for you!
-sw Resets renderers to default settings
-noFilter Disables bi-linear Filters
-noSmooth Disables polygon smoothing - may improve game performace
-disablePacking Disables the packed textures
-niltextures Disables wallpapers
-noborder Disables window borders
-NoFETextures Disables front-end textures
-noshowdamage Ships will not show damage effects
-stipple Stipples renderer alpha
-docklines Shows docking lines - is on by default
-gunlines Shows the target line - is on by default

Sound
-closeCaptioned Subtitled Cutscenes
-dsound Uses direct sound driver
-noSpeech Disables all voices
-reversestereo Reverses stereo - Left becomes Right and vice versa
-waveout Output converted to WAV

Debug
-debug Debug mode - useful after a crash
-nodebugInt Disables 3rd Mode Error
-intonsync Makes an integer 3 when a sync. error occurs
-gatherstats Gathers statistics
-heap (x) Global memory size heap setter - set (x) to a number - in MB
-lightlines Light lines are shown in debug mode
-textfeedback All feedback you recieve is stored in a text file in the main HW2 directory
-luatrace Logs scripting errors to ..\Homeworld 2\Bin\Release\Hw2.log

Multiplayer & Logging
-forceLAN Allows you to play a LAN game with other versions
-logOn Enables the text files after a multiplayer match
-logOff Disables Multiplayer Logs
-logonverbose Enables verbose logging files
-logfileloads Logs data files loaded
-aiplayerlog Logs AI player data in text files
-captaincyLogOff Disables end-of-match text reports
-captaincyLogOn Enables the text files after a battle
-statlogon Enables the Stats text files - use in conjunction with the above cheat. I think "above cheat" means -debug

Demos
-demorecord Records a demo - used in conjunction with the above cheat I think "above cheat" means -debug
-demoplay Plays a demo
-packetrecord Records packets during multiplayes skirmishes - used in conjunction with the above cheat I think "above cheat" means -debug
-packetplay Plays packet recordings
-debugsync Records packets and auto-saves frequently Might be useful to track down the "Out of Sync" error.

AI
-determcompplayer Computer players are more determined - makes for harder matches
-noretreat Disables AI retreat tactics
-noCompPlayers Eliminates all CPU players

Miscellany
-locale <language> Loads <language>.big instead of the default language (e.g. English.big)
-mod <modfile.big> Loads <modfile.big> as an additional *.big file. For those of us who have always wanted to combine the powers of 5 different mods to create VOL-MOD-TRON!
-disableAVI Auto-skips all cutscenes
-disableKatmai Disables KNI
-forcekatmai Use KNI
-nohint Disables the hints from the SM
-slowblits Enables slow screen blips
-smCentreCamera Focuses the camera at the center of the map when Home is pressed
-testNIS NIS testing
-testnisscript NIS testing using the SCRIPT files
-noMinimise Overrides Alt+Tab command when process is running Might help if you accidentally press these keys alot.
-noPause The game will not be auto-paused when Alt+Tab or the WinKey is pressed.
-freemouse Use F11 to toggle edge-of-screen pan (overrides all Function commands) If you find the mouseOnEdge panning annoying
-overridebigfile Overrides BIG files - for mods
-ignorebigfiles Same as above
-cdpath x:path Sets path to CD - x is name of CD drive
-prepath x:path Sets path to open files - x is name of drive

Unverified
-r2DDebug
-ssSetSuperSample
-ssSetCompression
-skeletonShip
-dp8sim
-dpsim
-conin
-maxplayers < >
-saveOutputFile
-bgSim
-todo (load defaults from teamcolours.lua)
-starfield
-luaplayer_console