Based on an affordable entry payment of a dollar and then upgrades and add-ons in-game are all based on a in-game store which would include additional city where they can get more troops to fight while in the game.
While in-game, players' towers also age and advance according to the number of days that they log-in to the game. If they do not log-on for a few days, the towers age again to the previous stage/time.
Players can have the option of permanently setting an age of the towers as an in-game purchase.
Heroes are also introduced in this game, as an add-on to run around in the game as support caster and damage output - depending on what types were selected.
While not in-game, Players will have access to a Citadel, Fortress or City; depending on what Hero class has been chosen, to heal the troops and Heroes.
This area will allow Players to build up ther cities in order to unlock more troops and abilities either via in-game coins or in-app purchases.