Before the rise of man brought the great rivalry between Pirate and Ninja, there was another natural feud between two animal species: Monkeys... and B[al]loons. No one knows how or why this epic war began, but both sides fight endlessly with ever greater wartime developments vying for domination of the world. All of the preceding is included absolutely nowhere in the game's design, and is merely a flavorful fantasy explaining why players seem to care so much about using monkeys to pop balloons.
Bloons Tower Defense (or BTD as it's abbreviated) is an ongoing Tower Defense series by Ninja Kiwi where monkeys (and other weapons) are used to pop a seemingly endless line of overly determined balloons of varying shapes, sizes, and speed. Though starting out with a simplified design palette, later installments of the series have evolved to include a great deal of complexity in both art and gameplay mechanics.
So far the series has 6 main installments. It started off as a spin-off of the lesser-known Bloons, a series of aim-and-power-meter puzzle games with many player-designed maps. However, it became so much more popular that it got its own spin-off, Bloons Super Monkey. This takes the form of a top-down aerial shooter starring the titular monkey from the BTD series, inspired by Raiden X. The basic goal is to pop a set number of bloons in each level, upgrading along the way to beat levels with increasingly strong Bloon formations. It even got its own sequel and a mobile remake thereof!
Three other spin-offs of this series exist:
- Bloons Monkey City, a tower-defense city-simulator combo with has elements of Facebook games where Player Versus Player is possible.
- Bloons TD Battles where PvP is the primary focus; the primary modes are Assault and Defensive. Assault has you and your opponent try to defeat each other by sending bloons, in addition to AI-spawned bloonsnote . Defensive instead focuses on surviving the AI bloons with reduced incomenote .
- A crossover of BTD and Adventure Time called Bloons Adventure Time TD, which had soft launch access for selected continents* on July 14, 2018, and was released worldwide on August 28 of the same year, with a PC release hitting Steam on January 16, 2019.
All versions of the game could be played at NinjaKiwi's site until Flash reached end-of-life (though you can download a stand-alone Ninja Kiwi Archive program that links to your account and lets you play them outside of a browser), and the original BTD, BTD2, BTD3, BTD4, BTD5, BTD Battles, and Bloons Monkey City are available on the iPhone. A similar version of BTD3 is available on DSiWare. Bloons Tower Defense 5 is also available on Steam with extra content, and you can even buy it on the Switch. Bloons Tower Defense 6 was confirmed by Ninja Kiwi here and was released on June 15th, 2018 for Android and iOS, later getting a release on Steam, the Epic Games Store, and Amazon.