Use these cheats to unlock something:
Unlock Ace Mode: Finish Normal mode
Unlock Medals: Play 'Campaign' mode or 'Free Mission' mode
Bronze Shooter Medal: Destroy 5 Enemy planes with the machine gun
Silver Shooter Medal: Down 15 enemy planes with machine gun
Gold Shooter Medal: Down 50 enemy planes with the machine gun
Bronze Wing Medal: Get 'S' Ranks on every mission on Normal
Silver Wing Medal: Earn 'S' Ranks on all 32 missions on Hard
Gold Wing Medal: Earn 'S' Ranks on all 32 missions on expert
Bronze Ace Medal: Destroy 200 enemy
Silver Ace Medal: Destroy 500 enemy
Gold Ace Medal: Destroy 1000 enemy
Grand Falcon Medal: Kill all 16 named planes in second play-through on Normal or Hard
Lightning Hammer Medal: Protect all 8 armored tanks on the ground
Unlock Expert mode: Finish Normal mode