Bloons Tower Defense 4 has got an expansion pack and it brings even more levels, towers and options. Now you can choose difficulty level along with many other options in that area. then you get to choose the track you want to play on. It is even more exciting than before but basic rules are still the same. You place your monkey turrets along the path and do your best to stop those pesky bloons from reaching the end of the road. You have limited amount of lives and the exact number depends on the difficulty level. If you need any additional info you can find it once you start the game. If you want to play 5th sequel of latest NinjaKiwi's BTD series that click here to play Bloon Tower Defense 5.