Half-Life Alpha

Half-Life 0.52, referred in the internal documentation as Half-Life Alpha, is an early build of Half-Life dated September 8, 1997; over a year before the game's release and before it entered a massive rework phase. Originally meant for press only, it was revealed by a Reddit user jackaljayzer in late 2012 and later released in 2013.

The build runs on an early version of Goldsource engine, being closer to Quake in some regards (the alpha's maps, for example, can even be loaded in Quake natively, although their texture and color data will be corrupt). It lacks many later features like the HEV suit, armor system, +use functionality, high resolution display support. The models of weapons and NPCs are far simpler than in the final game.

The build includes a cut down playable campaigh in six chapters (17 maps), roughly matching Unforeseen Consequences, Office Complex, "We've Got Hostiles!", Questionable Ethics, "Forget About Freeman!" and Lambda Core. The levels often combine visual simplicity and lack of polish with far more maze-like and intricate structure. The build comes with 15 pre-recorded Demo files, presumably recorded by a Valve employee.

Three technology demo maps - maindemo, silodemo and techdemo - are also included. They showcase Skeletal animation, models with high poly count, NPC interactions, colored lighting, entity shadows and sound effects.

Half-Life Alpha has limited multiplayer support and one MP map, early Stalkyard.

The disk with the game includes documentation meant for the press (HLSynopsis.doc with general story pitch and WalkThru.doc with detailed instruction for every level), several drivers for then-modern hardware, promo materials, and an early version of the soundtrack.

Tools

The 1.3 version of Worldcraft and the appropriate compilers (qbsp.exe, qrad.exe and vis.exe) included in the game files fully allows for creation of levels that can be launched in the build. However, being so ancient, WC 1.3 leads to a uncomfortable work process: it doesn't support the WASD control scheme, requires spacebar to be held down for mouselook to work, and runs poorly even on modern hardware. Despite that, properly set up tools can indeed compile the level built with it.