| Cast list |
| Robert Guillaume | as | Dr. Eli Vance (voice) |
| Merle Dandridge | as | Alyx Vance (voice) |
| Tony Todd | as | Vortigaunt (voice) |
| John Aylward | as | Dr. Arne Magnusson (voice) |
| Adam Baldwin | as | Citizens / Misc. Characters (unconfirmed) (voice) |
| Michelle Forbes | as | Dr. Judith Mossman (voice) |
| Mary Kae Irvin | as | Citizens / Misc. characters (voice) |
| John Patrick Lowrie | as | Citizens / Misc. characters (voice) |
| Ellen McLain | as | Overwatch (voice) |
| Harry S. Robins | as | Dr. Isaac Kleiner (voice) |
| Michael Shapiro | as | G-Man /Barney Calhoun (voice) |
