How about this for a new feature: a bank that you can put all different types of Coins in so that you don't accidentally spend them, and so that you can retrieve them at any time (but bely little/no interest (without upgrades?))
How about adding an option that allows you to turn off only some types of sound effects (for example, putting sound effects into two categories: in-game(when playing the tower defence part of the game) and out-of-game(when in the city building part of the game)), because I don't like having to hear bloons popping all the time, but I really like hearing the music that is heard when you go back to your city.
 "Anti-Idle: The Game"){kind=icon}
 "Bloons Monkey City"){kind=icon}
 "Planet Miner - The Search for the Elements of Life"){kind=icon}
 "League of Angels"){kind=icon}
 "Epic Battle Fantasy 4"){kind=icon}