more coding would help
music annoying. but...
interesting requirement of the user's mouse-movement skill. a clever usage of hitTest to make a maze program... but....
like the previous poster said, you can cheat by moving the mouse quickly towards the end "region" ... you might consider increasing the fps, since the onEnterFrame is not moving fast enough for the mouse motion. or, you can do frame independent motion detection... which is a bit harder than .hitTest, but still do-able. read Makar's Flash Game Programming Demystified
Makar also teaches you how to generate random mazes in his book. you can potentially have infinite levels by looking through the source in his book...