Free Mission
Just like in Ace Combat 4, this game also gives you the option of the "Free Mission", when you have completed the game, go to the main screen and select Free Mission. You can now play any mission in the game, using any plane you have previously bought.
Music Player
After completing the game, just go back to the Title screen and go to options. The Music Player option will now be available. With this, you can listen to all every single track from within the game... This is probably the ONLY place you will be able to do this, without having to actually play the game.
Even more difficulty settings...
When you have completed the game, there are a few more difficulty settings that you can choose from. These are great if you completed the game with ease, and want more of a challenge!
Falken
Get the missing parts from missions 12a, 12b, 16a, 16b, and 27a to unlock the Falken. You must destroy the hangar of each mission. For mission 12a, follow the river north, then go east at the fork in the river. You must be close for the hangar to show appear on radar. For mission 12b, after taking out the four radar sites, destroy enough targets and the hangar will show up near the smokestacks. The one in mission 16a is between the field HQ and the airfield. Mission 16b has it west of the river, between the airfield and oil refinery (south of the north-most river). The part on mission 27 is very close to the gun tower, in front of the tunnel.
Unlock F22A
Successfully complete arcade mode.
Unlock X-02
Get all the other aircraft except for the Falken to unlock the X-02.
Song decision
During one of the early stages of the campaign mode, Chopper will ask you about a song. Your next mission will depend on your answer ("Yes" or "No"). Also, at the end of the stage in which Edge gets rescued, Chopper will again ask you about the same song. Again, your "Yes" or "No" answer will decide which stage is next.
Falken
Get the missing parts from missions 12a, 12b, 16a, 16b, and 27a to unlock the Falken. You must destroy the hangar of each mission. For mission 12a, follow the river north, then go east at the fork in the river. You must be close for the hangar
to show appear on radar. For mission 12b, after taking out the four radar sites, destroy enough targets and the hangar will show up near the smokestacks. The one in mission 16a is between the field HQ and the airfield. Mission 16b has it west
of the river, between the airfield and oil refinery (south of the north-most river). The part on mission 27 is very close to the gun tower, in front of the tunnel.