Well, it did download the new version but it didn't update the old version, it just put the new version in a different folder. Still, it's a good example of the download and zip objects.
And I am able to open your game now, but it crashes shortly after the computer player starts moving, or immediately upon clicking with the mouse. Now that I think about it, maybe the crash has something to do with shooting in general, and the crash occurs when either the computer player tries to shoot at me or I try to shoot at it.
Also, is the tank supposed to sit for a few seconds and then go flying off the top of the screen? It's done that a couple times, much to my confusion.