could have been better.
first thing is that your using hitTestObject (or a variance of that), which uses the blue bounding box around the objects your hit-testing, that means that you're more likely to get hit by one of the enemy UFO's. There are some other problems too like multiple hits from the same object(while hes exploding). They're all easy enough bugs to fix and it has the possibility of being a quality game if you add some more weapons or levels to it.