AAT
To unlock the AAT without cheats beat every mission with a platinum medal
Extra levels
If you beat the game with all bronze medals on each mission you will unlock the Trade Federation Secrets level
If you beat the game with all Silver medals you will unlock the Couruscant Encounter level
If you beat the game with all Gold medals you will unlock the Dark Side level
Secret Platinum Medals
To unlock this medal you need to get near perfect stats on the level The requirements to get it well NOT show up when you beat the level
Sith Infiltrator
To unlock the Sith Infiltrator without cheats complete every mission with a gold medal on it