your game is full of bugs... quit button doesn't work... upon playing a second time, the creeps don't die after they should. Come on, dude, don't post until the thing is ready... people like me will give you a bad rating.
ok... you figured out how to do particles in flash... great. the game itself is lame... the field of view is too small to see incoming creeps, the gameplay is monotonous, i give you kudos for making a game and not sitting on your ass.
Are you still experiencing this? If so, please submit a bug report with as much detail as you can provide. Thanks.