You Know What It Takes ...
... to make great Flash toons! It's obvious you took your time, had patience and are very talented! The character designs are slick, the writing is fine and you know how to set a mood. This really is excellent for a first real go at animation.
My crits are:
SLOW PACING - I won't beat this into the ground since it already shows up in many reviews.
FRAME RATE - Try animating at 24fps. It may make the file size a bit bigger, but the action comes out much smoother and animating is actually a bit easier. Believe me, I used to do the 12fps thing as well until I decided to change to actual film rate and I haven't turned back.
ANIMATION CYCLES - Watch your beginning walk cycle. In a natural walk cycle, the left arm is back while the right leg is forward and vice-versa. Right now, you have the left leg and left arm moving in the same direction at the same time. I know you're new to animation so I suggest you get a hold of "How To Draw Cartoon Animation" by Preston Blair. It's an excellent book and displays various cycles like walking, running and jumping from both profile and front shots.
You have my respect as a Flash artist because your dedication to the discipline is obvious. I only see great things for you in the Flash arena and I wish you every success! This is truly excellent work!