To date over 6,500 lines of unique dialogue have been recorded and choreographed!
The voice acting team was formed with the help of a community project, where all the members of the forums were able to send their recordings impersonating any of the characters in the game. From hundreds of applications, the development team narrowed the choices down to a select few. The selection was based on the similarity to the original voice and the quality of recording.
Voice Acting Team Members
The Official members of the voice acting team are listed below .
- Adam "dravean" Dravean - Nihilanth
- Cris "Valo118" Mertens - HECU Marines, VOX System (post-Resonance Cascade)
- Janet Oliver Wilson (formerly Janet Sisk) - Black Ops Assassin
- Kevin "Debeerguy007" Sisk - Security Guard, Barney Calhoun, G-man, Eli Vance
- Lurana Hillard - Female Scientist
- Mike "CornetTheory" Hillard - Scientist, Isaac Kleiner
- Victoria "CatzEyes93" Teunissen - Tram Announcer, VOX system (pre-Resonance Cascade)
Unofficial members include those who entered and won the Black Mesa Community Project to create sounds for humans and aliens. 
The following media shows a little of the voice acting team's work.
- In the Half-Life games, Michael Shapiro did the voice acting for both the Security Guards / Barney Calhoun and the G-man. In Black Mesa, Kevin Sisk also voices the same characters.
- Michael Shapiro was contacted to voice act but declined, presumably due to being busy.