To celebrate the 25th Anniversary of the release of Half-Life we reunited the original development team to share their memories of creating Valve's first game.
| Actor | Role |
|---|---|
| KKelly BaileySelf | Self |
| YYahn BernierSelf | Self |
| KKen BirdwellSelf | Self |
| SSteve BondSelf | Self |
| DDario CasaliSelf | Self |
| GGreg CoomerSelf | Self |
| JJohn GuthrieSelf | Self |
| MMichael HarringtonSelf (as Mike Harrington) | Self (as Mike Harrington) |
| BBrett JohnsonSelf | Self |
| CChuck JonesSelf | Self |
 Marc LaidlawSelf | Self |
| KKaren LaurSelf | Self |
 Gabe NewellSelf | Self |
| DDave RillerSelf | Self |
| JJay StellySelf | Self |
| HHarry TeasleySelf | Self |
| SSteve TheodoreSelf | Self |
| BBill van BurenSelf | Self |
| DDouglas WoodSelf (as Doug Wood) | Self (as Doug Wood) |