I'm sorry, but I didn't really enjoy the game, but I've also been a new developer one day, and I'm sure that you will make much better game by the time. The easiest thing to improve here is to make Packman keep moving, also when you release the controller key. It can be done like this (is you use ActionScript 2.0):
In the packman's load event, set packman's rotation to be 0, like this:
onClipEvent(load) {
_rotation = 0;
Speed = 10;
}
//Then, in the Packman's enterFrame event, replace your current movement code with this:
onClipEvent (enterFrame) {
if (Key.isDown(Key.LEFT)) {
_rotation = 180;
}
if (Key.isDown(Key.RIGHT)) {
_rotation = 0;
}
if (Key.isDown(Key.UP)) {
_rotation = 270;
}
if (Key.isDown(Key.DOWN)) {
_rotation = 90;
}
//This will make Packman walk into the direction he points. Speed is a variable that stores how fast Packman walks.
this._x += Speed * Math.cos(_rotation * Math.PI / 180);
this._y += Speed * Math.sin(_rotation * Math.PI / 180);
}