Talk:Bloons Tower Defense 5/@comment-50.41.115.196-20111206211013/@comment-86.179.67.144-20111223071412

Like when you unlock a new tower or the 4th upgrade for one (on BTD4). Also, when you click on the tower and the next upgrade for one of the paths needs unlocking, there will be a bar. When it's full, it upgrades and starts working towards the next one. You can also go to the menu, click on the towers in the middle, find the tower you want to upgrade and look at the bottom part where it says XP. When the bar is full you will have every single upgrade for it.