Users who would like to run for moderator must be autoconfirmed and have at least 100 edits. Users can check their own edit count at Special:Preferences.
Half-Life 2: Episode One
▶ Launch it now*
🛒 Buy it on Steam (via Browser | Steam client*)
*Steam required, click here to download Steam.
Supported OS: 
Windows • 
Linux + 
SteamOS (See system requirements)
Steam Deck status: 
Playable - 
More info on ProtonDB
Also available from the following other storefronts or websites: 
Google Play (
NVIDIA Shield only)
Warning:(
macOS only) - This game does not work on macOS Catalina (version 10.15) or later due to the removal of support for 32-bit-only apps.Additionally, as of June 12, 2024, Valve has dropped Mac support for all GoldSrc, Source games.
| ||||||||
Half-Life 2: Episode One is the first in a series of games that reveal the aftermath of 
Half-Life 2 and launch a journey beyond City 17. It focuses on developing Alyx as a character.
Consciousness returns. Gordon and Alyx discover they've somehow escaped both the reactor explosion and the G-Man's malevolent grasp. Before they can ponder their miraculous survival, the crippled Citadel lurches back to life just long enough to initiate a self-destruct sequence. With Alyx at his side, Gordon must flee a city in chaos before the Citadel's final detonation turns City 17 into a toxic, mutant-infested crater.
Aside from the story, the game initially runs on 
Source 2006, which introduced new features such as HDR, Phong shading, and much more. The game was later upgraded to Source 2009, then again with Source 2013 Singleplayer.
Content
- Half-Life 2: Episode One (
episodic) - Half-Life 2 maps (
hl2) - Source shared (
hl2) 
Source 2013 Singleplayer engine branch
Chapters
| Half-Life 2: Episode One Chapters
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 Undue Alarm ep1_citadel_00 |
 Direct Intervention ep1_citadel_03 |
 Lowlife ep1_c17_00 |
 Urban Flight ep1_c17_01 |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 Exit 17 ep1_c17_05 |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Gallery
Limitations/Bugs
- For the list of Half-Life 2: Episode One bugs, see this GitHub page.
External links
| |||||||||||||||||
