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.

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!

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