decent tutorial, i have to give you at least 3 and half star because this is written in 2005, there are many things in this tutorial missing.
a) You can just hit Z and press forward and Z to just punch like superman so he never has to go through the whole action
b) hold down Z and press Right key, you slide across because the character is trying to perform an animation and walking at the same time, it needs "if key is down and key is down, _x+=stop; where variable for stop would be that speed to stop the character in its tracks.
c) the walking animation should not have to finish looping it's unnatural, you should make it so if key left is down play animation ablablbal else if key right play animation ablbalabl ELSE goto stance, so that if the Key is not DOWN! it goes straight to the stance, that way he's not walking in stationary through that animation
d) and the gravity is missing..
other then that my friend the tutorial is amazing! to learn the basics of AS not AS3 though, im still learning that haha it's a new world for me trying to program so strict!