CategoryPre-release builds

{|class="wikitable" style="width100%"
!Version or build number
!Date
!Working title
!First build date
!Notes
|-
!Half-Life Alpha|Version 0.52
|September 4, 1997
|''Half-Life''
|N/A
|Leaked ''Half-Life'' alpha.
|-
!Version 0.61
|Unknown
|''Half-Life''
|N/A
|Described in http//www.valvetime.net/threads/never-before-seen-half-life-development-documents.256932/ Sierra's internal notes. Also possibly seen in the {{YouTube|lxWUeyFadFY|video}} of Gabe Newell playing ''Half-Life''.
|-
!Half-Life Day One|Build 676
|August 31, 1998
|''Half-Life Day One''
|October 24, 1996
|OEM demo of ''Half-Life''.
|-
!Build 738
|November 1, 1998
|''Half-Life''
|October 24, 1996
|Release by CLASS group, 3 days before the final release.
|-
!Build 1672
|May 23, 2001
|''Half-Life'', ''Half-Life Blue Shift''
|October 24, 1996
|Leaked build of the cancelled Half-Life (Dreamcast port)|''Half-Life'' Dreamcast port.
|-
!Development of Half-Life 2|Build -7
|September 23, 2004
|''Half-Life Source'', ''wccounterstrikeCounter-Strike Source|Counter-Strike Source''
|September 30, 2004
|The "HL1 Ports" leak.
|-
!Development of Half-Life 2|Build -4
|September 26, 2004
|''Half-Life 2''
|September 30, 2004
|The Development of Half-Life 2 game|''Half-Life 2'' leak.
|-
!Source Particle Benchmark|Build 2915
|October 31, 2006
|Source Particle Benchmark
|November 7, 1998
|Benchmark of particle simulation of ''The Orange Box'' branch of the Source engine.
|}

Alpha, beta and other pre-release builds of Half-Life and Portal universe|''Half-Life'' series.

CategoryCut content
CategoryGames
CategoryPre-release material