I'm going to give a stark honest review, but coming from someone who grew up playing games and has a year of hobbyist programming under his belt,
I don't like it... But, I will make this review probably the most worthwhile one of them all by telling you how to correct it.
1. The Collision Detection and Gravity is all off, chances are this was made based off a tutorial, which is fine, we all need to learn, I'm still learning. But when making something by the aid of a tutorial, your final product after the tutorial is the least important thing and the least valuable to you. The value is the concepts and principals of Actionscript that you learn as a result of the tutorial. So I would suggest what I always do after learning something new with Actionscript. Study over what I've just learned, look at the original author's comments in the tutorial, and then close up the tutorial and the game I just "programmed" with the help of the tutorial... Then I open a fresh document, draw a couple of circles or squares, and apply different scripts to the to see what each individual section does, that way, I can gain knowledge from the tutorial. Doing so really helps, in fact, in a year's worth of weekends (I'm a hobby programmer, remember that) I've learned almost half of the stuff there is to know about Actionscript, and I can write the code for this platformer in my head, that's because I disassembled what I originally was taught, and made it my own through experimentation.
2. Art and Music are a Programmer's bread and butter, they fit along with the "Main Dish" which is programming. Your choice of music worked in an OK way, and the looping was nailed perfectly, but the art needs drastic improvement. You can't slap a stick-figure and a bunch of gradients together and call it a game, that just doesn't work... I suggest working on matching platforms to the background, I also understand that it's difficult, matching colors and such, but if you need to, begin with graytoned schemes, it will still be practice.
3. You can't place a whole bunch of restart buttons all over the place, if the player reaches an area in which they cant get back from, a game designer's ace-in-the-hole is to place a killer there to kill off the player and restart the level.
4. If a game is to be a true game, it must have a goal. You cant just expect people to run around with their jolly little stick figure and go "lalalalalalala, omg this gam3 is teh 1337 lemme get it a fiven!" players won't be happy without any goal in sight.
5. Disable the Context Menu, its a simple script, and it would stop players from right clicking and going to the "You Win" screen...