The gameplay of Bloons TD 5 is pretty much follows the standard tower defense layout. Players need to place different monkeys and structures (the towers in the game), each with their own individual strengths and abilities, and use them to pop or destroy balloons ("enemies" in the game) and prevent them from reaching the end of the map's track. The player will lose lives depending on the type of balloons that get past his defenses. Larger, advanced balloons costs more lives than ordinary ones.
Balloons come in different types and sizes and they'll travel along a fixed path. Players will also have a wide array of monkeys that they can dispatch along the tracks to defend against the balloon onslaught. Players will earn cash for every balloon popped, and they'll also earn extra cash when starting a new wave. Waves are short but plentiful. The number of waves also depend on the difficulty you chose before starting the map.
As players play the game, they'll earn EXP that will help them increase their ranks, unlocking more upgrades and towers. As you use towers, they'll also earn exp for popping balloons which will help in unlocking their upgrades. In addition to tower types, players can also employ special characters called "Agents" that they can buy and help them out in a battle.