Fix your ActionScript.
There's significant lag that's close to making the game unbearable, even on the lowest quality setting. Optimize your code or something, do something to the graphics - I'm not an expert on making smooth-running Flash games, but you should work on it.
If it weren't for that, the game might actually be fun and I would have rated it 5. But yeah, a nice effort, you at least went to the trouble of getting nice graphics even if you didn't make them yourself (which you need to learn how to do on an at least basic level if you're going to be making flash games).