Level 20 requires some pattern recognition. Usually clicking each lane in order from left to right when a car goes past them (assuming another isn't behind it) is a good idea. Also turn on the the two rightmost lights green to let one car past through each of them to give you a head start.
To the people who lag on each death: right-click, go to settings, and increase the amount of flash space to unlimited. This should fix it. Sorry for not mentioning this sooner. Also, do give it some leeway. This is a very old TD game. It was probably made before fast-forward coding was discovered.
Why is there no graphic options? I do want to play this, but the frame rate is so poor due my computer not being able to handle the water and rain effects. Because of this, my character runs toward a direction at least three seconds after I let go of the key. I don't know why some games are excluding this option more and more, but it has to stop. I'm not able to get The Badge of The Day unless I try a different computer, and that's just no fun.
@novy117 That would defeat the purpose. Watch the enemy stagger. That's your life bar. Also, report bugs by clicking on "Game Bug" not here. Don't forget screenshots.