| Unlockable: | How to Unlock: |
| A. Galinsky | Complete Special Objective in Campaign Mission 1 under the Recruit difficulty setting during a Quick Mission in Mission mode. |
| B. Gordon | Complete Special Objective in Campaign Mission 6 under any difficulty setting. |
| D. Munz | Complete Special Objective in Campaign Mission 2 under the Veteran difficulty setting during a Quick Mission in Mission mode. |
| G. Osadze | Complete Special Objective in Campaign Mission 5 under the Veteran difficulty setting during a Quick Mission in Mission mode. |
| H. Ramirez | Complete Special Objective in Campaign Mission 2 under any difficulty setting. |
| J. Stone | Complete Special Objective in Campaign Mission 4 under any difficulty setting. |
| K. Henkel | Complete Special Objective in Campaign Mission 3 under any difficulty setting. |
| N. Tunny | Complete Special Objective in Campaign Mission 3 under the Elite difficulty setting during a Quick Mission in Mission mode. |
| S. Grey | Complete Special Objective in Campaign Mission 5 under any difficulty setting. |
| S. Ibrahim | Complete Special Objective in Campaign Mission 6 under the Elite difficulty setting during a Quick Mission in Mission mode. |
| W. Jacobs | Complete Special Objective in Campaign Mission 1 under any difficulty setting. |