Maybe there could be an Achievement button for the current campaign. Clicking on it, the player is shown a list of accomplishments, with completed ones hi-lighted. If a player puts their cursor over where a achievement is, a popup shows the requirements for receiving that medal, and perhaps the benefits of having it. When a player completes or fails a campaign, a .png and text file would be generated that notes a player's accomplishments for that campaign.
COMMANDER ACHIEVEMENTS
Have over [$] in funds.
Established the maximum number of bases and fully developed them at game completion.
Captured and interrogated all alien species.
Completed the ufopedia.
Get a perfect grade for a council report.
No nations backed out of the X-COM project.
Lost less than [X] number of soldiers during the campaign.
Fully staffed an Avenger with fully promoted soldiers.
Didn't lose anyone on the Cydonia mission.
Killed
Didn't lose any civilians on a terror mission.