Interesting...
Strange little game you have here... my first thought was "I guess people just randomly hit 5 to add points to their account and that's the only reason this is on the Top 5," but it turned out much better than that. I agree that the firing rate is too slow, and on one level so many ghosts spawned I had a massive train chasing me around and lagging my Pentium II's ass off. A high rate of fire would've taken care of that easily. By the way, the total kills needed are actually 51, not 50. Good game though, and if this was your first attempt at Flash it absolutely rocked. Keep it up!