2005 Source 7 2459 wiki.sourceruns.org/wiki/Game_versions (Source 2004)
Options - Keyboard - Advanced - Enable developer console (~)

It's not possible to play it out of the box - now Steam uses .vpk instead .gcf and requires a full update.

First it must be extracted with GCFScape developer.valvesoftware.com/wiki/GCFScape

One way to launch the game - the digital copy must be in your Steam library:
1. Install the game from the discs.
Do not unpack .cab manually - you'll get corrupted sound-files since vo-NovaProspekt-mo_protectfather01.
2. Extract all .gcf (except source_lv - low violence) in \Steam\steamapps to one folder.
3. Name the folder as you like (Half-Life 2 005) and move it to \Steam\steamapps\common.
4. Uninstall the game.
6. Launch Steam (login is required) at first and only then launch the game with hl2 .exe or the shortcut.
No login/digital copy - you'll get only some maps of Chapter 1/6.

Since the unpacked \hl2\maps with .bsp and \hl2\maps\graphs with .ain have a different modified time, you'll recieve the infamous problem "Node Graph out of date. Rebuilding" in the beginning of each maps, and related one "A.I. Disabled" after loading your saves: all you have to do is set the modified time of .ain to .bsp ones (a deleted scene "intro .bsp" youtu.be/pUv9zOtY-do is optional) - not a second newer - with BulkFileChanger nirsoft.net/utils/bulk_file_changer.html (actions - change time - pay attention on GMT).

Steam-Properties-Launch options/Shortcut-Properties: +r_lod 0+cl_detaildist 10000+rope_wind_dist 10000
r_lod 0 - "will effectively make every render as if you are close to them"
cl_detaildist - "distance at which detail props (grass) are shown" 100 : 1
rope_wind_dist - "applying small wind gusts to ropes" 100 : 1

Access to all chapters: sv_unlockedchapters 15 /to all maps: map "name".

Text language: Win+R - regedit: HKEY_CURRENT_USER\SOFTWARE\Valve\Steam\steamglobal

Speech language (hl2_sound_vo_language_000-006-dir .vpk) depends on Steam internal settings and must be auto downloaded into \Steam\steamapps\common\Half-Life 2\hl2 - it needs to be extracted (open language_dir) with GCFScape developer.valvesoftware.com/wiki/GCFScape to \Half-Life 2\hl2_language

2004 does not use \sound\combined unlike 2005-2022 - non-English speech may varies.

Source 2004/2006 use natural glossy shaders of weapon/crowbar-HL2-headcrabs/Dog unlike 2007/2013.

MSAA has rare artefacts (red/white lines) unlike MSAA+SGSSAA or SSAA or SSAA+MSAA+SGSSAA with nvidiaProfileInspector - use "Enhance the application setting" while MSAA in-game (4x nvidia) must be on.

3D sound is activated without "snd_digital/legacy_surround 1" unlike 2006-2022. Since Vista, it needs to be restored with Creative ALchemy, but standart buffers/duration 4/25 (delay 100ms - alike input-lag) give lots of clicks here (5.1 works) - use 3/5 (elusive delay 15ms) instead, tested with X-Fi Ti CMSS-3D Headphone.

2153/2187/2459 have a "flashlight issue" in DX9 on DX12 (GT 1030) while on DX11 (HD Graphics 4000) do not have one - modified d3d9 .dll of dgVoodoo2 github.com/dege-diosg/dgVoodoo2/releases fixes it.

Since 2459 a "sunken wheels issue" at Chapter 1 (Strider) is appeared - a fix is within client/server .dll.

Thanks a lot for sharing!

Source 5 2153 archive.org/details/Sierra_Valve_Half-Life_2_Windows_DX9_2004_Eng
Source 5 2153 archive.org/details/Nova_HalfLife2USACollectors
Source 6 2187 archive.org/details/Half-Life_2_DVD_Retail_VENGEANCE
Source 7 2459 archive.org/details/Valve_Half-Life_2_Game_of_the_Year_Edition_Windows_2005_Eng
Source 7 2707/2803 archive.org/details/half-life-2-2006-valve-dvd
Source 7 2733 archive.org/details/half-life-2-episode-one-2006-valve-dvd
Source 7 2707/3224 archive.org/details/The_Orange_Box_USA
Source 7 2707/3264 archive.org/details/Nova_HalfLife2EpisodePackUSAEurope