Half-Life 1 Beta but it's Garry's Mod

Porting stuff from Absolute Zero modSeriously, AZ is a great mod, they did huge amount of work recreating HL beta content. Sadly the mod died a year ago, so

PhysGun, Half Life 2 Beta Wiki

How to Play Half-life 1 and Half-life 2 in VR

Steam Workshop::HL2001 - Main Collection

Garry's Mod (2012) - The Cutting Room Floor

Steam Workshop::Garrys Mod 9 / Half-Life 2 Beta Addons

Steam Workshop::Garry's Mod to Half Life Collection

Half-Life: Source Playermodels - Skymods

Half-Life 2 mod turns Valve's FPS into an Amnesia-style horror game

Half-Life 2 Beta, Half-Life Wiki

Garry's Mod 13 Xash beta 0.7 file - ModDB

Does anyone know why the Half life 2 skull texture appears on the

Half-Life 1 Alpha - Ivan and Barney by KillroyFreeman on DeviantArt