The game looks great
I have a few suggestions though:
-Can you add a screen that lists all of the buttons and controls?
-When the game switches to another map, can you make the transition a little smoother, or hide it behind a brief "fade to black"
-Can you disable the plane's controls during the title screen? If I keep increasing throttle during the title screen, I can start the game with full throttle.
-Where did the brushed metal backgrounds for the difficulty buttons come from?
By the way, I set a new record for easy mode: 4 seconds!
==============Some of my Games and Ideas===========
Sky Warrior: http://www.alice.org/community/showthread.php?t=6291
Health Bars: http://www.alice.org/community/showthread.php?p=36968#post36968
Sky Warrior: Dual Force: http://www.alice.org/community/showthread.php?t=7174
Want to make your own space game? http://www.alice.org/community/showthread.php?t=6389