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Buildings in Bloons Monkey City are required in order to use and upgrade towers.
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One primary difference between this game and the others in the Bloons series is the addition of buildings. Another mode is Battle with Friends, in which a player can play one of the four game modes with a friend, not a random player, by entering a code for the player's private lobby.
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Players earn a club ticket every day at 7 PM, or they can receive one club ticket from the daily wheel. The card selection can be chosen ahead of time when playing against a friend in a private lobby, but is random when playing other opponents. The last mode is Club Battles, in which players can play with up to three of the six game-modifying "cards". Using the games' skill-based matching system, players can be automatically matched with one another. All three game mode objectives are to outlast the opponent in surviving the bloon attacks. The cards have two functions: sending bloons to the enemy player, which, like in Assault Mode, will give the player who sends the bloons extra income and placing down a tower. In "Card Battles" mode, the players choose from a selection of cards to use in their games. Players can spend money to increase their income. In "Defense" mode, the players play a natural game with the screen split vertically. However, the players are also given the ability to purchase additional bloons that gives eco and sending them to the opponent can overwhelming them. For example, round 7 in BTD Battles would be round 13 in BTD5. In Assault Mode and Battle Arena, each player normally progresses through the levels that are usually equal to 2x-1 in terms of BTD5 levels.
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The gameplay is similar to that in Bloons TD 5 but two players compete against one another in one of four game modes.
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