Random Defence, best flash game in a while (addictive)

I just tried doing it with red tech, but only the grenades. Works good until you get the really fast ones with decent HP, then the grenades inaccuracy is just too bad and they skate right on through. I even tried stacking like 15 right in a line, thinking that the first will get through the others will just run into the misfires, but it ends up that like every 3rd one gets through and there are too many that it eventually just burns your life to zero without getting very far....