Bloons TD Battles is the multiplayer, competitive version of Bloons TD 5, with different strategies, tracks, and other features. In this game, players use their money to send bloons (Assault Mode only).
The main menu of Bloons TD Battles has 5 options:
Quick Battle: Searches for a random opponent to play against.
Private Battle: Lets the player create battles and join battles created by other players, but only if the Battle ID is known by the joining player.
High Scores: Checks the leaderboard for the highest battle score.
All bloons have an income change, either increasing or decreasing (or neither) the player's only initial source of extra money besides Banana Farms in the game, a 6-second income boost.
Thus, as the player obtains no money from popping bloons, it is important to constantly improve their income by sending bloons.
In Defend Mode on the other hand, the player's only way of improving their income is by purchasing periodic income boosts.
In assault mode, you start off with $250 income, and $650 right off from the get-go. This means that you will get $250 per 6 seconds. By spending money to send out bloons at your opponent, you can increase the amount of money you get every 6 seconds. For example, if you send out 8 grouped red bloons, your income will increase by $1.
As rounds progress, stronger and stronger bloons get unlocked, meaning that you will have to improve your defenses. For instance, spaced Pink Bloons are unlocked on round 4, and spaced Black Bloons are unlocked on round 6.
Bloon sends can be Regenerating or Camo. These modifiers are unlocked on round 8 and 12 respectively. Changing bloon types this way will incur an additional multiplier on the cost of the bloon. For instance, the cost multiplies by ×1.8 and ×2.2 respectively, or ×3.8 if both are applied. MOAB-Class Bloons are unaffected, but their non-blimp children spawned are.
The next towers, which are unlocked upon reaching a 50, include the Ice Tower, Boomerang Thrower, Glue Gunner and Monkey Buccaneer. Unlike the towers you get from the start, you must pay a small amount of medallions (usually 10-20) to unlock them, as well as additional medallions for their respective Tier 4 upgrades.
Rounds are mostly the even-only equivalent of those in Bloons TD 5, with only a few exceptions. For instance, Round 43 represents Round 85 of BTD5 instead of 86, and Round 12 that is Round 25 of BTD5 instead of 24. However, in the iOS version, the rounds are from the Flash rounds -1, so Round 12 is Round 24 of BTD5 instead of 25. Round 43 is the only round not to follow this rule, as it contains the normal round 85. As a result, dangerous bloons like M.O.A.B Class Bloons appears less and later on mobile. However, version 3.1 on mobile made short rounds had more bloons so the player can react better.
A round only begins 4 seconds after one player has popped all computer-generated bloons in the previous round, or 8 seconds after all the natural bloons have been spawned, whichever occurs earlier.
The player earns 2 for losing (0 for disconnecting or surrendering on the first 13 rounds), 5 for a win, and 7 for a flawless win (7 for a flawless win is only available in the mobile version).
10 is awarded for winning. Losing rewards is only 2.
There are 2 "abilities" to use during the thirty-second time before battles: the spy and an extra tower slot. The spy costs 3 and let you see the opponent's towers and the extra tower slot costs 1 and let you choose 1 extra tower for a total of five towers
In the mobile edition, the bonus is chosen randomly by a roll and can be any tower, even towers you didn't yet unlock (your bonus is Tier 4). Rolling costs 1 and rerolling costs 3. Spying requires 2.
The player can choose between Assault and Defensive Mode.
In Assault Mode, the player attempts to crush their opponent with bloons, similar to the Bloons TD Battles before the update with defend mode. After Round 30, all player-sent bloons will have their speed boosted by 20% each wave. Sending bloons also increases their salary every few seconds. Except if its a MOAB or bigger it gets decreased.
In Defend Mode, the player attempts to outlast their opponent. They cannot send any bloons, and have an initial income of $50. It can be increased by purchasing income boosts, which have a cooldown based on the income increase; the higher the boost, the longer the cooldown, but also the more cost-effective the boost is. Income is capped at $3,000.
Small income boost - Increases income by $2. Cost: $50. Takes 150 seconds to "break even", as in, pay for itself.
Medium income boost - Increases income by $15. Cost: $300. Takes 120 seconds to break even.
Large income boost - Increases income by $70. Cost: $1,000. Takes approximately 90 seconds to break even.
Huge income boost - Increases income by $700. Cost: $7,500. Takes approximately 66 seconds to break even.
MOAB-class bloons gain 20% speed and 40% health per wave after round 30.
Selling towers returns 70% of the purchasing price rather than 80%.
In-game chat and the Dartling Gun were added to Bloons TD Battles in the same update that added the track Hydro Dam to the game. However, there is no chat for Bloons TD Battles Mobile because there is no usage of the keyboard in the mobile version. To chat a player must press enter and type the message. Press enter again to send it. The /ping command can be used in the chat also to determine the ping speed.