The rank 31 thing is quite annoying... keep trying to fast upgrade my towers to save myself and then I get the kreds pop-up and lose control of the game. Last time it happened to me flash crashed for some reason and I was left with a black box. Apart from this it's a good game...
 "Wake the Royalty"){kind=icon}
 "Infectonator : World Dominator"){kind=icon}
 "Bloons Tower Defense 4"){kind=icon}
 "Level Up!"){kind=icon}