Ahhh AS2 how i love you, i am dipping my toes into AS3 and that is a whole new world, the idea of never using actionscript on movie clips themselves is terrifying, instead using listeners. Anyway the script was solid, i still dislike when games have gravity like we're on Mars(Spaceman Craig Keee-Kuuu-Keee-Kuuu) the more static gravity like QUICK UP AND DOWN is more my style. But i simply loved the explanation but the color's are not good for the eyes to read ( and no i have 19 inch acer LCD ) no low contrast, it's better to use white on dark green :D.. But i give you top score because the information is there... Question
You say you put the actions for the wall, ceiling on themselves.. Can't you just as well put that in the character if the character's instance name hitTarget instance of the movieclips wall ceiling, yadayad and keep it all inside the main character.. (Only problem being that if you do create enemies, you'd have to copy paste that into their MC instead of just.. ahh never mind your way seams better regarding that issue...
And the A for attack was nice but if you didn't hold down A it just went to frame 1 of the stance, you might consider running an animation and just put _root.hero.gotoAndStop(1);
Anyway just amazing :) full score from me...